{"product_id":"effective-interest-rate","title":"Effective Interest Rate Calculator","description":"\u003cstyle\u003e\n.eir-calculator {\n  --ink: #0f172a;\n  --muted: #475569;\n  --border: #e2e8f0;\n  --surface: #ffffff;\n  --tint: #f8fafc;\n  --primary: #1d4ed8;\n  --accent: #c2410c;\n  --accent-hover: #9a3412;\n  --chart-1: #1e40af;\n  --chart-2: #0d9488;\n  --chart-3: #7c3aed;\n  --chart-4: #be185d;\n  --chart-5: #334155;\n  width: 100%;\n  max-width: 1200px;\n  margin: 0 auto;\n  color: var(--ink);\n  background: var(--surface);\n  border: 1px solid var(--border);\n  border-radius: 8px;\n  box-shadow: 0 1px 2px rgba(15,23,42,.06);\n  font-family: -apple-system, BlinkMacSystemFont, \"Segoe UI\", Roboto, Helvetica, Arial, sans-serif;\n  font-size: 15px;\n  line-height: 1.55;\n  container-type: inline-size;\n  overflow-wrap: anywhere;\n}\n.eir-calculator,\n.eir-calculator *,\n.eir-calculator *::before,\n.eir-calculator *::after {\n  box-sizing: border-box;\n}\n.eir-calculator :where(.eir-header,.eir-toolbar,.eir-workspace,.eir-chart-card,.eir-table-card,.eir-education,.eir-rate-anatomy) {\n  min-width: 0;\n}\n.eir-calculator h2,\n.eir-calculator h3,\n.eir-calculator p {\n  margin-top: 0;\n}\n.eir-calculator h2 {\n  margin-bottom: 8px;\n  font-size: 24px;\n  line-height: 1.25;\n  font-weight: 700;\n  letter-spacing: -.02em;\n}\n.eir-calculator h3 {\n  margin-bottom: 12px;\n  font-size: 18px;\n  line-height: 1.35;\n  font-weight: 650;\n}\n.eir-calculator a {\n  color: var(--primary);\n  text-decoration-thickness: 1px;\n  text-underline-offset: 2px;\n}\n.eir-calculator a:hover {\n  text-decoration-thickness: 2px;\n}\n.eir-calculator button,\n.eir-calculator input,\n.eir-calculator select {\n  font: inherit;\n}\n.eir-calculator button,\n.eir-calculator select,\n.eir-calculator input {\n  min-height: 44px;\n}\n.eir-calculator button:focus-visible,\n.eir-calculator input:focus-visible,\n.eir-calculator select:focus-visible,\n.eir-calculator summary:focus-visible,\n.eir-calculator a:focus-visible {\n  outline: 3px solid rgba(29,78,216,.38);\n  outline-offset: 2px;\n}\n.eir-header {\n  padding: 24px 24px 16px;\n  border-bottom: 1px solid var(--border);\n  background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);\n  border-radius: 8px 8px 0 0;\n}\n.eir-header \u003e p {\n  max-width: 760px;\n  margin-bottom: 16px;\n  color: var(--muted);\n}\n.eir-pills {\n  display: flex;\n  flex-wrap: wrap;\n  gap: 8px;\n  min-width: 0;\n}\n.eir-pill {\n  display: inline-flex;\n  align-items: center;\n  gap: 6px;\n  min-width: 0;\n  padding: 4px 8px;\n  border: 1px solid var(--border);\n  border-radius: 999px;\n  background: var(--surface);\n  color: var(--muted);\n  font-size: 13px;\n  font-weight: 500;\n  line-height: 1.4;\n}\n.eir-pill strong {\n  color: var(--ink);\n  font-variant-numeric: tabular-nums;\n}\n.eir-toolbar {\n  display: flex;\n  flex-wrap: wrap;\n  align-items: center;\n  gap: 8px;\n  padding: 16px 24px;\n  border-bottom: 1px solid var(--border);\n  background: var(--surface);\n}\n.eir-button {\n  display: inline-flex;\n  align-items: center;\n  justify-content: center;\n  gap: 10px;\n  min-width: 0;\n  padding: 11px 16px;\n  border: 1px solid var(--border);\n  border-radius: 6px;\n  background: var(--surface);\n  color: var(--ink);\n  font-size: 15px;\n  font-weight: 650;\n  line-height: 1;\n  cursor: pointer;\n  box-shadow: 0 1px 2px rgba(15,23,42,.06);\n  transition: background .15s ease, border-color .15s ease, transform .15s ease, box-shadow .15s ease;\n}\n.eir-button:hover {\n  border-color: #cbd5e1;\n  background: var(--tint);\n  box-shadow: 0 2px 5px rgba(15,23,42,.10);\n}\n.eir-button:active {\n  transform: translateY(1px);\n}\n.eir-download {\n  padding: 12px 18px;\n  border-color: var(--accent);\n  background: var(--accent);\n  color: #ffffff;\n  white-space: nowrap;\n}\n.eir-download:hover,\n.eir-download:active {\n  border-color: var(--accent-hover);\n  background: var(--accent-hover);\n}\n.eir-button svg {\n  width: 18px;\n  height: 18px;\n  flex: 0 0 auto;\n  fill: none;\n  stroke: currentColor;\n  stroke-width: 2;\n  stroke-linecap: round;\n  stroke-linejoin: round;\n}\n.eir-workspace {\n  display: grid;\n  grid-template-columns: minmax(0,1fr);\n  gap: 16px;\n  padding: 24px;\n  background: var(--tint);\n  border-bottom: 1px solid var(--border);\n}\n.eir-panel {\n  min-width: 0;\n  padding: 20px;\n  border: 1px solid var(--border);\n  border-radius: 8px;\n  background: var(--surface);\n  box-shadow: 0 1px 2px rgba(15,23,42,.06);\n}\n.eir-fields {\n  display: grid;\n  grid-template-columns: repeat(auto-fit,minmax(210px,1fr));\n  gap: 16px;\n  min-width: 0;\n}\n.eir-field {\n  display: flex;\n  flex-direction: column;\n  gap: 6px;\n  min-width: 0;\n}\n.eir-field label {\n  color: var(--ink);\n  font-size: 14px;\n  font-weight: 600;\n}\n.eir-field input,\n.eir-field select {\n  width: 100%;\n  min-width: 0;\n  padding: 9px 11px;\n  border: 1px solid #cbd5e1;\n  border-radius: 6px;\n  background: #ffffff;\n  color: var(--ink);\n  font-size: 15px;\n  font-weight: 400;\n  font-variant-numeric: tabular-nums;\n}\n.eir-field input:hover,\n.eir-field select:hover {\n  border-color: #94a3b8;\n}\n.eir-helper {\n  min-height: 38px;\n  color: var(--muted);\n  font-size: 13px;\n  font-weight: 500;\n  line-height: 1.45;\n}\n.eir-error {\n  min-height: 19px;\n  color: #b91c1c;\n  font-size: 13px;\n  font-weight: 600;\n  line-height: 1.4;\n}\n.eir-field[aria-invalid=\"true\"] input,\n.eir-field[aria-invalid=\"true\"] select {\n  border-color: #b91c1c;\n  box-shadow: 0 0 0 2px rgba(185,28,28,.12);\n}\n.eir-advanced {\n  margin-top: 16px;\n  border-top: 1px solid var(--border);\n  padding-top: 12px;\n}\n.eir-advanced summary {\n  display: inline-flex;\n  align-items: center;\n  min-height: 40px;\n  color: var(--primary);\n  font-size: 14px;\n  font-weight: 650;\n  cursor: pointer;\n}\n.eir-advanced .eir-fields {\n  margin-top: 12px;\n}\n.eir-results {\n  display: grid;\n  align-content: start;\n  gap: 16px;\n  min-width: 0;\n}\n.eir-primary-result {\n  padding: 20px;\n  border: 1px solid #bfdbfe;\n  border-radius: 8px;\n  background: #eff6ff;\n}\n.eir-primary-result span {\n  display: block;\n  margin-bottom: 4px;\n  color: #1e3a8a;\n  font-size: 13px;\n  font-weight: 650;\n}\n.eir-primary-result strong {\n  display: block;\n  color: #172554;\n  font-size: 30px;\n  line-height: 1.15;\n  font-weight: 700;\n  font-variant-numeric: tabular-nums;\n  overflow-wrap: anywhere;\n}\n.eir-primary-result p {\n  margin: 8px 0 0;\n  color: #1e3a8a;\n  font-size: 13px;\n  font-weight: 500;\n}\n.eir-result-grid {\n  display: grid;\n  grid-template-columns: repeat(auto-fit,minmax(150px,1fr));\n  gap: 12px;\n  min-width: 0;\n}\n.eir-result-card {\n  min-width: 0;\n  padding: 14px;\n  border: 1px solid var(--border);\n  border-radius: 8px;\n  background: var(--surface);\n}\n.eir-result-card span {\n  display: block;\n  margin-bottom: 4px;\n  color: var(--muted);\n  font-size: 13px;\n  font-weight: 600;\n}\n.eir-result-card strong {\n  display: block;\n  color: var(--ink);\n  font-size: 20px;\n  line-height: 1.3;\n  font-weight: 700;\n  font-variant-numeric: tabular-nums;\n  overflow-wrap: anywhere;\n}\n.eir-inline-note {\n  margin: 0;\n  padding: 10px 12px;\n  border: 1px solid var(--border);\n  border-radius: 6px;\n  background: var(--tint);\n  color: var(--muted);\n  font-size: 13px;\n  font-weight: 500;\n}\n.eir-rate-anatomy,\n.eir-chart-card,\n.eir-table-card,\n.eir-education {\n  margin: 24px;\n  min-width: 0;\n}\n.eir-rate-anatomy {\n  padding: 20px;\n  border: 1px solid var(--border);\n  border-radius: 8px;\n  background: var(--surface);\n}\n.eir-anatomy-grid {\n  display: grid;\n  grid-template-columns: repeat(auto-fit,minmax(170px,1fr));\n  gap: 12px;\n  min-width: 0;\n}\n.eir-anatomy-item {\n  min-width: 0;\n  padding: 14px;\n  border-left: 4px solid var(--chart-1);\n  border-radius: 6px;\n  background: var(--tint);\n}\n.eir-anatomy-item:nth-child(2) {\n  border-left-color: var(--chart-2);\n}\n.eir-anatomy-item:nth-child(3) {\n  border-left-color: var(--chart-3);\n}\n.eir-anatomy-item span {\n  display: block;\n  color: var(--muted);\n  font-size: 13px;\n  font-weight: 600;\n}\n.eir-anatomy-item strong {\n  display: block;\n  margin-top: 4px;\n  font-size: 20px;\n  line-height: 1.3;\n  font-weight: 700;\n  font-variant-numeric: tabular-nums;\n}\n.eir-chart-card,\n.eir-table-card {\n  padding: 20px;\n  border: 1px solid var(--border);\n  border-radius: 8px;\n  background: var(--surface);\n  box-shadow: 0 1px 2px rgba(15,23,42,.06);\n}\n.eir-chart-intro {\n  max-width: 780px;\n  margin-bottom: 16px;\n  color: var(--muted);\n  font-size: 13px;\n  font-weight: 500;\n}\n.eir-chart-cluster {\n  display: grid;\n  grid-template-columns: minmax(0,1fr);\n  gap: 20px;\n  align-items: start;\n  justify-items: center;\n  width: 100%;\n  max-width: 920px;\n  margin: 0 auto;\n  min-width: 0;\n}\n.eir-plot-wrap {\n  width: 100%;\n  min-width: 0;\n}\n.eir-chart-svg {\n  display: block;\n  width: 100%;\n  min-width: 0;\n  height: auto;\n  max-height: 430px;\n  overflow: visible;\n}\n.eir-chart-svg text {\n  fill: var(--muted);\n  font-family: inherit;\n  font-size: 13px;\n  font-weight: 500;\n}\n.eir-chart-svg .eir-grid-line {\n  stroke: #cbd5e1;\n  stroke-width: 1;\n}\n.eir-chart-svg .eir-axis-line {\n  stroke: #64748b;\n  stroke-width: 1.2;\n}\n.eir-chart-svg .eir-series-one {\n  fill: none;\n  stroke: var(--chart-1);\n  stroke-width: 3.5;\n  stroke-linecap: round;\n  stroke-linejoin: round;\n}\n.eir-chart-svg .eir-series-two {\n  fill: none;\n  stroke: var(--chart-2);\n  stroke-width: 3.5;\n  stroke-linecap: round;\n  stroke-linejoin: round;\n  stroke-dasharray: 8 6;\n}\n.eir-chart-svg .eir-area-one {\n  fill: rgba(30,64,175,.10);\n  stroke: none;\n}\n.eir-chart-svg .eir-end-dot-one {\n  fill: var(--chart-1);\n  stroke: #ffffff;\n  stroke-width: 2;\n}\n.eir-chart-svg .eir-end-dot-two {\n  fill: var(--chart-2);\n  stroke: #ffffff;\n  stroke-width: 2;\n}\n.eir-legend {\n  display: grid;\n  gap: 10px;\n  width: 100%;\n  max-width: 330px;\n  min-width: 0;\n}\n.eir-legend-row {\n  display: grid;\n  grid-template-columns: 14px minmax(0,1fr) auto;\n  align-items: center;\n  gap: 10px;\n  min-width: 0;\n  padding: 8px 10px;\n  border: 1px solid var(--border);\n  border-radius: 6px;\n  background: var(--tint);\n  font-size: 13px;\n  font-weight: 600;\n}\n.eir-legend-swatch {\n  width: 14px;\n  height: 4px;\n  border-radius: 4px;\n  background: var(--chart-1);\n}\n.eir-legend-row:nth-child(2) .eir-legend-swatch {\n  background: var(--chart-2);\n}\n.eir-legend-value {\n  color: var(--ink);\n  font-variant-numeric: tabular-nums;\n  white-space: nowrap;\n}\n.eir-chart-callout,\n.eir-table-note {\n  margin-top: 16px;\n  padding: 10px 12px;\n  border: 1px solid var(--border);\n  border-radius: 6px;\n  background: var(--tint);\n  color: var(--muted);\n  font-size: 13px;\n  font-weight: 500;\n}\n.eir-chart-summary {\n  position: absolute;\n  width: 1px;\n  height: 1px;\n  padding: 0;\n  margin: -1px;\n  overflow: hidden;\n  clip: rect(0,0,0,0);\n  white-space: nowrap;\n  border: 0;\n}\n.eir-empty-state {\n  width: 100%;\n  max-width: 520px;\n  margin: 8px auto 0;\n  padding: 16px;\n  border: 1px dashed #94a3b8;\n  border-radius: 6px;\n  background: var(--tint);\n  color: var(--muted);\n  text-align: center;\n  font-size: 13px;\n  font-weight: 600;\n}\n.eir-chart-card.eir-safe-stack .eir-chart-cluster {\n  grid-template-columns: minmax(0,1fr);\n  gap: 24px;\n}\n.eir-chart-card.eir-safe-stack .eir-legend {\n  max-width: 520px;\n}\n.eir-chart-card.eir-safe-stack .eir-chart-callout {\n  margin-top: 20px;\n}\n.eir-table-overflow {\n  width: 100%;\n  max-width: 100%;\n  min-width: 0;\n  overflow-x: auto;\n  overscroll-behavior-inline: contain;\n  border: 1px solid var(--border);\n  border-radius: 6px;\n}\n.eir-table {\n  width: 100%;\n  min-width: 680px;\n  border-collapse: collapse;\n  font-size: 13px;\n  font-variant-numeric: tabular-nums;\n}\n.eir-table th,\n.eir-table td {\n  padding: 10px 12px;\n  border-bottom: 1px solid var(--border);\n  text-align: right;\n  vertical-align: middle;\n}\n.eir-table th:first-child,\n.eir-table td:first-child {\n  text-align: left;\n}\n.eir-table th {\n  background: #172554;\n  color: #ffffff;\n  font-weight: 700;\n  white-space: nowrap;\n}\n.eir-table tbody tr:nth-child(even) {\n  background: var(--tint);\n}\n.eir-table tbody tr:hover {\n  background: #eef2ff;\n}\n.eir-table tbody tr:last-child td {\n  border-bottom: 0;\n  font-weight: 700;\n}\n.eir-table-card.eir-safe-table-stack .eir-table-note {\n  margin-top: 20px;\n}\n.eir-education {\n  padding: 24px;\n  border-top: 1px solid var(--border);\n  background: var(--tint);\n}\n.eir-education-inner {\n  max-width: 880px;\n  margin: 0 auto;\n}\n.eir-education h2 {\n  margin-top: 28px;\n  font-size: 22px;\n}\n.eir-education h2:first-child {\n  margin-top: 0;\n}\n.eir-education h3 {\n  margin-top: 20px;\n}\n.eir-education p,\n.eir-education li {\n  color: #334155;\n}\n.eir-education ul,\n.eir-education ol {\n  padding-left: 22px;\n}\n.eir-formula {\n  display: block;\n  margin: 12px 0;\n  padding: 12px;\n  border-left: 4px solid var(--primary);\n  border-radius: 0 6px 6px 0;\n  background: #eff6ff;\n  color: #172554;\n  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;\n  font-size: 15px;\n  font-weight: 650;\n  overflow-wrap: anywhere;\n}\n@container (min-width: 900px) {\n  .eir-calculator .eir-workspace {\n    grid-template-columns: minmax(0,1.08fr) minmax(340px,.92fr);\n  }\n}\n@container (min-width: 640px) {\n  .eir-calculator .eir-chart-cluster {\n    grid-template-columns: minmax(0,1fr) minmax(230px,300px);\n    gap: 24px;\n    align-items: center;\n  }\n  .eir-calculator .eir-chart-card.eir-safe-stack .eir-chart-cluster {\n    grid-template-columns: minmax(0,1fr);\n  }\n}\n@container (max-width: 639px) {\n  .eir-calculator .eir-header,\n  .eir-calculator .eir-toolbar,\n  .eir-calculator .eir-workspace,\n  .eir-calculator .eir-education {\n    padding-left: 16px;\n    padding-right: 16px;\n  }\n  .eir-calculator .eir-rate-anatomy,\n  .eir-calculator .eir-chart-card,\n  .eir-calculator .eir-table-card,\n  .eir-calculator .eir-education {\n    margin-left: 16px;\n    margin-right: 16px;\n  }\n  .eir-calculator .eir-panel,\n  .eir-calculator .eir-chart-card,\n  .eir-calculator .eir-table-card,\n  .eir-calculator .eir-rate-anatomy {\n    padding: 16px;\n  }\n  .eir-calculator .eir-fields {\n    grid-template-columns: minmax(0,1fr);\n  }\n  .eir-calculator .eir-result-grid {\n    grid-template-columns: repeat(2,minmax(0,1fr));\n  }\n  .eir-calculator .eir-chart-cluster {\n    gap: 20px;\n  }\n  .eir-calculator .eir-chart-callout,\n  .eir-calculator .eir-table-note {\n    margin-top: 12px;\n  }\n}\n@container (max-width: 380px) {\n  .eir-calculator .eir-result-grid {\n    grid-template-columns: minmax(0,1fr);\n  }\n  .eir-calculator .eir-button {\n    width: 100%;\n  }\n  .eir-calculator .eir-toolbar {\n    align-items: stretch;\n  }\n  .eir-calculator .eir-primary-result strong {\n    font-size: 27px;\n  }\n  .eir-calculator .eir-legend-row {\n    grid-template-columns: 14px minmax(0,1fr);\n  }\n  .eir-calculator .eir-legend-value {\n    grid-column: 2;\n  }\n}\n\u003c\/style\u003e\n\u003cdiv class=\"eir-calculator\" data-calculator-root\u003e\n  \u003csection class=\"eir-header\"\u003e\n    \u003ch2\u003eEffective Interest Rate Calculator\u003c\/h2\u003e\n    \u003cp\u003eConvert a nominal, periodic, or effective annual rate into comparable terms, then see how compounding changes a balance over time.\u003c\/p\u003e\n    \u003cdiv class=\"eir-pills\" aria-label=\"Live calculation summary\"\u003e\n      \u003cspan class=\"eir-pill\"\u003eFrequency \u003cstrong class=\"eir-pill-frequency\"\u003eMonthly\u003c\/strong\u003e\u003c\/span\u003e\n      \u003cspan class=\"eir-pill\"\u003ePeriodic \u003cstrong class=\"eir-pill-periodic\"\u003e0.8333%\u003c\/strong\u003e\u003c\/span\u003e\n      \u003cspan class=\"eir-pill\"\u003eEffective \u003cstrong class=\"eir-pill-effective\"\u003e10.4713%\u003c\/strong\u003e\u003c\/span\u003e\n      \u003cspan class=\"eir-pill\"\u003eTerm \u003cstrong class=\"eir-pill-term\"\u003e5 years\u003c\/strong\u003e\u003c\/span\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n  \u003cdiv class=\"eir-toolbar\"\u003e\n    \u003cbutton class=\"eir-button eir-download\" type=\"button\"\u003e\n      \u003csvg viewbox=\"0 0 24 24\" aria-hidden=\"true\"\u003e\u003cpath d=\"M12 3v12m0 0 4-4m-4 4-4-4M5 19h14\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n      \u003cspan\u003eDownload Excel\u003c\/span\u003e\n    \u003c\/button\u003e\n    \u003cbutton class=\"eir-button eir-reset\" type=\"button\"\u003e\n      \u003csvg viewbox=\"0 0 24 24\" aria-hidden=\"true\"\u003e\u003cpath d=\"M4 4v6h6M20 20v-6h-6M5.5 15a7 7 0 0 0 11.7 2.6L20 14M4 10l2.8-3.6A7 7 0 0 1 18.5 9\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n      \u003cspan\u003eReset\u003c\/span\u003e\n    \u003c\/button\u003e\n  \u003c\/div\u003e\n  \u003csection class=\"eir-workspace\"\u003e\n    \u003cdiv class=\"eir-panel eir-input-panel\"\u003e\n      \u003ch3\u003eInterest-rate assumptions\u003c\/h3\u003e\n      \u003cdiv class=\"eir-fields\"\u003e\n        \u003cdiv class=\"eir-field\"\u003e\n          \u003clabel for=\"eir-rate-mode\"\u003eRate entered\u003c\/label\u003e\n          \u003cselect id=\"eir-rate-mode\" class=\"eir-rate-mode\"\u003e\n            \u003coption value=\"nominal\" selected\u003eNominal annual rate\u003c\/option\u003e\n            \u003coption value=\"periodic\"\u003ePeriodic rate\u003c\/option\u003e\n            \u003coption value=\"effective\"\u003eEffective annual rate\u003c\/option\u003e\n          \u003c\/select\u003e\n          \u003cdiv class=\"eir-helper\"\u003eChoose which quoted rate you already know.\u003c\/div\u003e\n          \u003cdiv class=\"eir-error\" aria-live=\"polite\"\u003e\u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"eir-field\"\u003e\n          \u003clabel for=\"eir-rate-value\" class=\"eir-rate-label\"\u003eNominal annual rate\u003c\/label\u003e\n          \u003cinput id=\"eir-rate-value\" class=\"eir-rate-value\" type=\"text\" inputmode=\"decimal\" value=\"10.00 %\" autocomplete=\"off\" aria-describedby=\"eir-rate-help eir-rate-error\"\u003e\n          \u003cdiv id=\"eir-rate-help\" class=\"eir-helper eir-rate-help\"\u003eThe stated yearly rate before compounding is included.\u003c\/div\u003e\n          \u003cdiv id=\"eir-rate-error\" class=\"eir-error\" aria-live=\"polite\"\u003e\u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"eir-field\"\u003e\n          \u003clabel for=\"eir-frequency\"\u003eCompounding frequency\u003c\/label\u003e\n          \u003cselect id=\"eir-frequency\" class=\"eir-frequency\"\u003e\n            \u003coption value=\"1\"\u003eAnnual\u003c\/option\u003e\n            \u003coption value=\"2\"\u003eSemi-annual\u003c\/option\u003e\n            \u003coption value=\"4\"\u003eQuarterly\u003c\/option\u003e\n            \u003coption value=\"12\" selected\u003eMonthly\u003c\/option\u003e\n            \u003coption value=\"52\"\u003eWeekly\u003c\/option\u003e\n            \u003coption value=\"365.242\"\u003eDaily (average year)\u003c\/option\u003e\n            \u003coption value=\"360\"\u003eDaily (360\/year)\u003c\/option\u003e\n            \u003coption value=\"365\"\u003eDaily (365\/year)\u003c\/option\u003e\n            \u003coption value=\"continuous\"\u003eContinuous\u003c\/option\u003e\n            \u003coption value=\"custom\"\u003eCustom\u003c\/option\u003e\n          \u003c\/select\u003e\n          \u003cdiv class=\"eir-helper\"\u003eHow often interest is calculated and added during one year.\u003c\/div\u003e\n          \u003cdiv class=\"eir-error\" aria-live=\"polite\"\u003e\u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"eir-field\"\u003e\n          \u003clabel for=\"eir-term\"\u003eTerm in years\u003c\/label\u003e\n          \u003cinput id=\"eir-term\" class=\"eir-term\" type=\"text\" inputmode=\"decimal\" value=\"5\" autocomplete=\"off\" aria-describedby=\"eir-term-help eir-term-error\"\u003e\n          \u003cdiv id=\"eir-term-help\" class=\"eir-helper\"\u003eUse a decimal for partial years, such as 2.5.\u003c\/div\u003e\n          \u003cdiv id=\"eir-term-error\" class=\"eir-error\" aria-live=\"polite\"\u003e\u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"eir-field\"\u003e\n          \u003clabel for=\"eir-balance\"\u003eStarting balance\u003c\/label\u003e\n          \u003cinput id=\"eir-balance\" class=\"eir-balance\" type=\"text\" inputmode=\"decimal\" value=\"$10,000.00\" autocomplete=\"off\" aria-describedby=\"eir-balance-help eir-balance-error\"\u003e\n          \u003cdiv id=\"eir-balance-help\" class=\"eir-helper\"\u003eOptional principal used to estimate future balance and interest.\u003c\/div\u003e\n          \u003cdiv id=\"eir-balance-error\" class=\"eir-error\" aria-live=\"polite\"\u003e\u003c\/div\u003e\n        \u003c\/div\u003e\n      \u003c\/div\u003e\n      \u003cdetails class=\"eir-advanced\"\u003e\n        \u003csummary\u003eAdvanced frequency settings\u003c\/summary\u003e\n        \u003cdiv class=\"eir-fields\"\u003e\n          \u003cdiv class=\"eir-field eir-custom-field\" hidden\u003e\n            \u003clabel for=\"eir-custom-periods\"\u003eCustom periods per year\u003c\/label\u003e\n            \u003cinput id=\"eir-custom-periods\" class=\"eir-custom-periods\" type=\"text\" inputmode=\"decimal\" value=\"24\" autocomplete=\"off\" aria-describedby=\"eir-custom-help eir-custom-error\"\u003e\n            \u003cdiv id=\"eir-custom-help\" class=\"eir-helper\"\u003eEnter a positive number of equal compounding periods per year.\u003c\/div\u003e\n            \u003cdiv id=\"eir-custom-error\" class=\"eir-error\" aria-live=\"polite\"\u003e\u003c\/div\u003e\n          \u003c\/div\u003e\n        \u003c\/div\u003e\n      \u003c\/details\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"eir-results\" aria-label=\"Calculation results\"\u003e\n      \u003cdiv class=\"eir-primary-result\" aria-live=\"polite\"\u003e\n        \u003cspan\u003eEffective interest rate\u003c\/span\u003e\n        \u003cstrong class=\"eir-effective-output\"\u003e10.4713%\u003c\/strong\u003e\n        \u003cp class=\"eir-primary-description\"\u003eA 10.0000% nominal rate compounded monthly becomes 10.4713% over one year.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"eir-result-grid\"\u003e\n        \u003cdiv class=\"eir-result-card\"\u003e\n\u003cspan\u003eNominal annual rate\u003c\/span\u003e\u003cstrong class=\"eir-nominal-output\"\u003e10.0000%\u003c\/strong\u003e\n\u003c\/div\u003e\n        \u003cdiv class=\"eir-result-card\"\u003e\n\u003cspan\u003ePeriodic rate\u003c\/span\u003e\u003cstrong class=\"eir-periodic-output\"\u003e0.8333%\u003c\/strong\u003e\n\u003c\/div\u003e\n        \u003cdiv class=\"eir-result-card\"\u003e\n\u003cspan\u003eCompounding uplift\u003c\/span\u003e\u003cstrong class=\"eir-uplift-output\"\u003e0.4713 pp\u003c\/strong\u003e\n\u003c\/div\u003e\n        \u003cdiv class=\"eir-result-card\"\u003e\n\u003cspan\u003eCompounding periods\u003c\/span\u003e\u003cstrong class=\"eir-periods-output\"\u003e60\u003c\/strong\u003e\n\u003c\/div\u003e\n        \u003cdiv class=\"eir-result-card\"\u003e\n\u003cspan\u003eFinal balance\u003c\/span\u003e\u003cstrong class=\"eir-final-output\"\u003e$16,453.09\u003c\/strong\u003e\n\u003c\/div\u003e\n        \u003cdiv class=\"eir-result-card\"\u003e\n\u003cspan\u003eTotal interest\u003c\/span\u003e\u003cstrong class=\"eir-interest-output\"\u003e$6,453.09\u003c\/strong\u003e\n\u003c\/div\u003e\n      \u003c\/div\u003e\n      \u003cp class=\"eir-inline-note eir-result-note\"\u003eThe effective rate reflects compounding only. Product fees, taxes, payment timing, and changing rates are not included.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n  \u003csection class=\"eir-rate-anatomy\"\u003e\n    \u003ch3\u003eOne-year rate anatomy\u003c\/h3\u003e\n    \u003cdiv class=\"eir-anatomy-grid\"\u003e\n      \u003cdiv class=\"eir-anatomy-item\"\u003e\n\u003cspan\u003eQuoted nominal rate\u003c\/span\u003e\u003cstrong class=\"eir-anatomy-nominal\"\u003e10.0000%\u003c\/strong\u003e\n\u003c\/div\u003e\n      \u003cdiv class=\"eir-anatomy-item\"\u003e\n\u003cspan\u003eEffective annual rate\u003c\/span\u003e\u003cstrong class=\"eir-anatomy-effective\"\u003e10.4713%\u003c\/strong\u003e\n\u003c\/div\u003e\n      \u003cdiv class=\"eir-anatomy-item\"\u003e\n\u003cspan\u003eInterest on interest\u003c\/span\u003e\u003cstrong class=\"eir-anatomy-uplift\"\u003e0.4713 pp\u003c\/strong\u003e\n\u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n  \u003csection class=\"eir-chart-card\" data-eir-chart-card\u003e\n    \u003ch3\u003eBalance path: compound interest vs. simple interest\u003c\/h3\u003e\n    \u003cp class=\"eir-chart-intro\"\u003eThe solid line applies the effective annual rate. The dashed line applies the nominal rate only to the original principal, making the compounding effect visible.\u003c\/p\u003e\n    \u003cdiv class=\"eir-chart-content\"\u003e\n      \u003cdiv class=\"eir-chart-cluster\"\u003e\n        \u003cdiv class=\"eir-plot-wrap\"\u003e\n          \u003csvg class=\"eir-chart-svg\" viewbox=\"0 0 760 430\" role=\"img\" aria-labelledby=\"eir-chart-title eir-chart-desc\"\u003e\n            \u003ctitle id=\"eir-chart-title\"\u003eBalance over time\u003c\/title\u003e\n            \u003cdesc id=\"eir-chart-desc\"\u003eCompound and simple-interest balance paths based on the current inputs.\u003c\/desc\u003e\n          \u003c\/svg\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"eir-legend\" aria-label=\"Chart legend\"\u003e\u003c\/div\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"eir-chart-callout\"\u003e\u003c\/div\u003e\n      \u003cdiv class=\"eir-chart-summary\" role=\"region\" aria-label=\"Accessible chart data\"\u003e\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"eir-empty-state\" hidden\u003eEnter a positive balance and term to see the chart.\u003c\/div\u003e\n  \u003c\/section\u003e\n  \u003csection class=\"eir-table-card\" data-eir-table-card\u003e\n    \u003ch3\u003eBalance schedule\u003c\/h3\u003e\n    \u003cdiv class=\"eir-table-overflow\"\u003e\n      \u003ctable class=\"eir-table\"\u003e\n        \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eYear\u003c\/th\u003e\n\u003cth\u003eCompound balance\u003c\/th\u003e\n\u003cth\u003eSimple-interest balance\u003c\/th\u003e\n\u003cth\u003eCompound interest\u003c\/th\u003e\n\u003cth\u003eCompounding advantage\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n        \u003ctbody class=\"eir-schedule-body\"\u003e\u003c\/tbody\u003e\n      \u003c\/table\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"eir-table-note\"\u003eRows use the same unrounded model as the headline results and Excel workbook. Partial final years are included when the term is not a whole number.\u003c\/div\u003e\n  \u003c\/section\u003e\n  \u003csection class=\"eir-table-card\" data-eir-table-card\u003e\n    \u003ch3\u003eCompounding-frequency comparison\u003c\/h3\u003e\n    \u003cdiv class=\"eir-table-overflow\"\u003e\n      \u003ctable class=\"eir-table\"\u003e\n        \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eFrequency\u003c\/th\u003e\n\u003cth\u003ePeriods per year\u003c\/th\u003e\n\u003cth\u003ePeriodic rate\u003c\/th\u003e\n\u003cth\u003eEffective annual rate\u003c\/th\u003e\n\u003cth\u003eOne-year interest\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n        \u003ctbody class=\"eir-comparison-body\"\u003e\u003c\/tbody\u003e\n      \u003c\/table\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"eir-table-note\"\u003eThis comparison holds the derived nominal annual rate constant, so the effect of changing only the compounding frequency is isolated.\u003c\/div\u003e\n  \u003c\/section\u003e\n  \u003csection class=\"eir-education\"\u003e\n    \u003cdiv class=\"eir-education-inner\"\u003e\n      \u003ch2\u003eWhat does this effective interest rate calculator estimate?\u003c\/h2\u003e\n      \u003cp\u003eThis calculator converts among three related rate measures: the nominal annual rate, the rate applied in each compounding period, and the effective annual interest rate. The effective rate is the actual one-year growth rate created by compounding. It is useful when two loans, deposit accounts, or investment illustrations quote similar annual rates but compound at different frequencies. The balance projection then applies the calculated effective rate over the term you enter.\u003c\/p\u003e\n      \u003cp\u003eThe tool isolates compounding mathematics. It does not automatically include origination fees, account charges, taxes, penalties, variable-rate changes, irregular deposits, withdrawals, or scheduled loan payments. For consumer-credit comparisons, review the complete disclosure rather than relying on one percentage alone. The \u003ca href=\"https:\/\/www.consumerfinance.gov\/ask-cfpb\/what-is-a-loan-estimate-en-1995\/\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eConsumer Financial Protection Bureau\u003c\/a\u003e explains why fees and other loan terms matter alongside the rate.\u003c\/p\u003e\n      \u003ch2\u003eHow should each input be used?\u003c\/h2\u003e\n      \u003ch3\u003eRate entered\u003c\/h3\u003e\n      \u003cp\u003eSelect the type of rate you already know. Choose \u003cstrong\u003eNominal annual rate\u003c\/strong\u003e for a stated yearly rate before intra-year compounding. Choose \u003cstrong\u003ePeriodic rate\u003c\/strong\u003e when the contract gives the rate charged each month, quarter, or other period. Choose \u003cstrong\u003eEffective annual rate\u003c\/strong\u003e when you already know the true one-year growth rate and need the equivalent nominal or periodic rate. Only one rate is required because the calculator derives the other two.\u003c\/p\u003e\n      \u003ch3\u003eRate value\u003c\/h3\u003e\n      \u003cp\u003eEnter the selected rate as a percentage, such as 8.5 or 8.5%. Higher positive rates increase the effective rate, projected ending balance, and total interest. A blank, nonnumeric, or negative value is treated as invalid because this version is designed for standard positive-rate comparisons. Very high values can produce very large balances, so always confirm that the percentage and frequency match the quoted product.\u003c\/p\u003e\n      \u003ch3\u003eCompounding frequency\u003c\/h3\u003e\n      \u003cp\u003eFrequency is the number of times interest is calculated and added in one year. Annual means once, semi-annual means twice, quarterly means four times, monthly means twelve times, and weekly means fifty-two times. The daily choices preserve common market conventions: an average calendar year, a 360-day convention, or a 365-day convention. Continuous compounding uses an exponential limit and has no discrete periodic rate. Custom frequency is available for unusual contracts; enter a positive number of equal periods per year.\u003c\/p\u003e\n      \u003ch3\u003eTerm and starting balance\u003c\/h3\u003e\n      \u003cp\u003eThe term controls the projection horizon and may include decimals. A term of 2.5 means two and a half years. The starting balance is optional for rate conversion but required for meaningful dollar projections and the chart. A larger balance changes dollar interest proportionally but does not change any percentage rate. The model assumes no additional cash flows during the term.\u003c\/p\u003e\n      \u003ch2\u003eHow is the effective interest rate calculated?\u003c\/h2\u003e\n      \u003cp\u003eFor discrete compounding, the calculator uses the standard effective annual rate equation:\u003c\/p\u003e\n      \u003cspan class=\"eir-formula\"\u003eEIR = (1 + r \/ m)^m − 1\u003c\/span\u003e\n      \u003cp\u003eHere, \u003cstrong\u003er\u003c\/strong\u003e is the nominal annual rate written as a decimal and \u003cstrong\u003em\u003c\/strong\u003e is the number of compounding periods per year. The periodic rate is r divided by m. For continuous compounding, the model uses EIR = e^r − 1. When you enter a periodic or effective rate instead, the equations are rearranged to solve for the nominal rate. Full precision is retained in the model; rounding occurs only for display and export formatting.\u003c\/p\u003e\n      \u003cp\u003eThe final balance is the starting balance multiplied by (1 + EIR) raised to the term. This is equivalent to compounding at the selected periodic rate for the corresponding number of periods. The \u003ca href=\"https:\/\/www.investor.gov\/introduction-investing\/investing-basics\/glossary\/compound-interest\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eU.S. Securities and Exchange Commission's Investor.gov\u003c\/a\u003e provides a practical explanation of compound interest and why time magnifies its effect.\u003c\/p\u003e\n      \u003ch2\u003eHow should the results be interpreted?\u003c\/h2\u003e\n      \u003cp\u003e\u003cstrong\u003eEffective interest rate\u003c\/strong\u003e is the primary comparison metric. When compounding occurs more than once a year and the nominal rate is positive, the effective rate is normally higher than the nominal rate. \u003cstrong\u003ePeriodic rate\u003c\/strong\u003e is the percentage applied each compounding period. \u003cstrong\u003eCompounding uplift\u003c\/strong\u003e is the difference between the effective and nominal annual rates, expressed in percentage points rather than percent change.\u003c\/p\u003e\n      \u003cp\u003e\u003cstrong\u003eCompounding periods\u003c\/strong\u003e is the selected frequency multiplied by the term; continuous compounding is labeled separately. \u003cstrong\u003eFinal balance\u003c\/strong\u003e is the projected amount after the full term. \u003cstrong\u003eTotal interest\u003c\/strong\u003e is the final balance minus the starting balance. A zero starting balance produces zero dollar amounts even though the percentage-rate conversion remains valid.\u003c\/p\u003e\n      \u003cp\u003eThe chart compares compound growth with simple interest. Compound growth repeatedly earns or charges interest on prior interest, while the simple-interest line applies the nominal rate only to the original principal. The gap between the lines is the cumulative compounding advantage. The schedule exposes the exact yearly values behind the chart, and the frequency table shows how the same nominal rate changes when only the compounding convention changes.\u003c\/p\u003e\n      \u003ch2\u003eWhat are the most common mistakes?\u003c\/h2\u003e\n      \u003cul\u003e\n        \u003cli\u003eConfusing a nominal annual rate with an effective annual rate.\u003c\/li\u003e\n        \u003cli\u003eUsing monthly compounding while entering a daily periodic rate, or vice versa.\u003c\/li\u003e\n        \u003cli\u003eComparing an effective rate with an APR that includes or excludes different fees.\u003c\/li\u003e\n        \u003cli\u003eAssuming a fixed rate when the real product can reset over time.\u003c\/li\u003e\n        \u003cli\u003eUsing a 360-day convention when the contract specifies 365 days.\u003c\/li\u003e\n        \u003cli\u003eReading a percentage-point uplift as a percent increase.\u003c\/li\u003e\n      \u003c\/ul\u003e\n      \u003cp\u003eFor savings accounts, the Federal Reserve's \u003ca href=\"https:\/\/www.federalreserve.gov\/consumerscommunities\/consumer-resources.htm\" target=\"_blank\" rel=\"noopener noreferrer\"\u003econsumer resources\u003c\/a\u003e can help you understand broader account terms. For any real financial decision, verify the compounding convention, fee treatment, cash-flow timing, and disclosure definitions in the official product documents.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n\u003c\/div\u003e","brand":"FinancialModelsLab","offers":[{"title":"Default Title","offer_id":49909481734387,"sku":"effective-interest-rate","price":0.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0522\/6191\/2762\/files\/effective-interest-rate.webp?v=1783935395","url":"https:\/\/financialmodelslab.com\/products\/effective-interest-rate","provider":"Financial Models Lab","version":"1.0","type":"link"}