APR Calculator
APR & Loan Cost Calculator
Estimate the nominal APR, effective APR, periodic payment, and full borrowing cost after financed and upfront fees.
Loan specification
Cash amount stated in the loan agreement.
Quoted annual rate before fees.
Repayment duration in the selected unit.
How often installments are made.
How often the quoted rate compounds.
Financed fees that accrue interest.
Upfront fees not added to the balance.
Live results
Effective APR
—
Enter a valid loan specification to calculate the all-in annualized cost.
Total repayment breakdown
Principal, interest, and fees shown as parts of total cash paid.
Balance and cumulative interest
See how the outstanding balance declines while interest accumulates over the loan term.
Annual repayment schedule
Annual totals are derived from the same period-by-period model used for the results and Excel workbook.
| Year | Payments | Starting balance | Principal paid | Interest paid | Ending balance | Cumulative interest |
|---|
How to use and interpret the APR calculator
This calculator estimates the cost of a fixed-rate, fully amortizing loan with equal payments. It separates the advertised nominal interest rate from APR, which incorporates qualifying fees, and from effective APR, which also reflects compounding. The result is useful for comparing loan offers that have different fee structures, payment intervals, or compounding conventions. It is an analytical estimate rather than a lender disclosure, legal determination, or personalized financial recommendation.
What each input means
- Loan amount is the stated amount borrowed before fees. Enter the contractual principal, not the total of future payments. A larger amount generally increases the payment and total interest in dollars, although the percentage APR can fall when a fixed fee is spread across a larger principal.
- Nominal interest rate is the quoted annual rate before fees. Enter a percentage such as 6% rather than a decimal such as 0.06. A higher rate raises the periodic payment, total interest, EAR, APR, and effective APR.
- Loan term is the repayment duration. Choose years or months; switching the unit converts the current value. A longer term usually lowers each payment but increases total interest because the balance remains outstanding longer. Very short terms can make upfront fees produce a much higher APR.
- Payment frequency controls how often installments occur. Monthly means 12 payments per year, bi-weekly means 26, and weekly means 52. The calculator converts the compounding rate into an equivalent rate for the chosen payment interval.
- Compounding frequency specifies how often interest is applied under the quoted nominal rate. More frequent compounding increases the effective annual rate when the nominal rate is unchanged. This field may differ from payment frequency.
- Fees rolled into loan are financed charges added to the balance. Because they are part of financed principal, they accrue interest and increase both the payment and APR. Examples may include financed origination charges or points, depending on the agreement.
- Fees paid separately are upfront charges that reduce the borrower’s net proceeds but are not added to the amortizing balance. They increase APR even though the lender does not charge periodic interest on them in this model. Separate fees must remain below the loan amount so net proceeds stay positive.
Understanding the results
Annual Percentage Rate is the nominal annualized rate implied by the payment stream and net loan proceeds. It is calculated by solving for the periodic rate that equates the present value of payments with the cash actually received, then multiplying that rate by the number of payments per year. The Consumer Financial Protection Bureau explains why APR and interest rate can differ.
Effective APR compounds the periodic APR over a full year. It is normally at least as high as nominal APR when there is more than one payment period per year. Effective Annual Rate performs a similar compounding adjustment on the quoted interest rate but excludes fees. Comparing EAR with effective APR isolates the effect of fees on the all-in annualized cost.
Payment per period is the equal installment required to amortize the loan amount plus financed fees. Total interest is the sum of interest across all scheduled payments. Total fees combines rolled and separately paid fees. Total finance charge equals interest plus all modeled fees, while total payments equals the original loan amount plus that finance charge. A zero result is possible only when the rate and all fees are zero.
Periodic equivalent rate is the rate used for each payment interval after reconciling payment and compounding frequencies. Equivalent nominal rate annualizes that periodic rate without compounding. Approximate APR uses a simplified finance-charge formula; it can be useful as a reasonableness check but may differ materially from the iterative APR, especially for long terms, large fees, or unusual frequencies.
How the model works
Equivalent periodic rate = (1 + nominal rate ÷ compounding periods)compounding periods ÷ payment periods − 1. Payment = financed principal × periodic rate ÷ (1 − (1 + periodic rate)−number of payments). APR is then solved iteratively from the present value of the payment stream and net proceeds.
The model uses full precision internally and rounds only for display and export. When the nominal rate is zero, payment is financed principal divided by the number of payments. The final scheduled payment is adjusted by a few cents when necessary so the ending balance is exactly zero rather than slightly negative because of floating-point arithmetic.
Reading the charts and schedule
The repayment donut divides total cash paid into original principal, interest, financed fees, and upfront fees. A larger interest segment indicates that rate or term is driving cost; a larger fee segment indicates that charges are materially increasing APR. The timeline plots remaining balance against cumulative interest. Slow early balance reduction is typical for long amortizing loans because a larger share of early payments goes to interest.
The annual table aggregates every payment into calendar-like loan years. Starting balance plus interest minus principal reduction reconciles to the ending balance. The final row should end at zero. The Excel export includes the current inputs, results, breakdown, complete payment-level schedule, and methodology notes, making it easier to compare scenarios outside the page.
Comparison tips and common mistakes
Compare loans using the same amount, term, and expected holding period. A lower rate with a large upfront fee may be more expensive if the loan is repaid early, while a higher-rate loan with minimal fees may cost more over a long term. Confirm which charges a lender includes in its official disclosure: legal rules vary by product and jurisdiction. U.S. closed-end credit disclosure is governed by Regulation Z §1026.22 and related Appendix J. European consumer-credit calculations are addressed in Directive (EU) 2023/2225.
Common errors include entering the interest rate as a decimal, counting the same fee as both rolled and separate, comparing APRs from loans with different terms without reviewing total cost, and assuming every lender uses identical timing conventions. Treat this estimate as a transparent comparison model and reconcile it with the lender’s official disclosure before making a decision.