Loan Calculator

What this loan comparison estimates

This calculator compares up to three fixed-rate installment loans using a month-by-month amortization model. It estimates the scheduled payment, first-month cash outflow, payoff time, total interest, total fees, total amount paid, and a fee-adjusted effective annual cost. The comparison is designed for personal loans, vehicle loans, equipment financing, and other loans with regular monthly payments. Results are estimates rather than lender disclosures or personalized financial advice.

How to enter each loan offer

Offer name and Include switch

The offer name is optional and appears throughout the results, charts, schedule, and Excel workbook. Use a lender name or a short label such as “Credit union” or “36-month offer.” The Include switch determines whether an offer participates in the comparison. Turning it off removes that loan from winners, charts, tables, and the export without deleting its inputs.

Loan amount

Enter the principal the lender will advance before any separately paid fee. This field is required and must be greater than zero. Comparing offers is most meaningful when the loan amounts are equal. A larger principal increases the payment, total interest, and total amount paid. A common mistake is entering the cash you receive after an origination fee rather than the contractual principal; use the upfront-fee field to keep those amounts separate.

Annual interest rate

Enter the fixed annual nominal rate as a percentage. Zero is allowed for promotional financing. A higher rate generally raises both the monthly payment and lifetime interest. The calculator converts the annual rate to a monthly rate by dividing by 12. A lender’s disclosed APR may already incorporate certain fees, while a note rate may not. For consumer-credit disclosures, the Consumer Financial Protection Bureau explains why rate and fee information should be reviewed together.

Term in years

Enter the contractual repayment term, from a fraction of a year up to 50 years. The model rounds the result to the nearest whole month. A longer term usually lowers the required monthly payment but keeps the balance outstanding longer, which often increases total interest. A shorter term usually costs less overall but requires more monthly cash. Avoid comparing only the payment: a low payment can be produced simply by extending the term.

Upfront fee, monthly fee, and extra payment

The upfront fee is paid at closing and increases total cost immediately; examples include an origination or processing charge. The monthly fee is added to every payment while the loan remains open. Extra monthly payment is applied directly to principal after the scheduled interest is covered. Extra payments can shorten the payoff period and reduce interest, but the model assumes the lender allows them without a prepayment penalty. Verify that assumption in the contract. The Federal Trade Commission and the electronic Code of Federal Regulations, Regulation Z provide background on consumer-credit disclosures and advertising rules.

How to interpret the results

Lowest total cost and savings

Lowest total cost means principal plus modeled interest plus upfront and monthly fees. Because each borrower must repay principal, the more decision-relevant difference between equal-size offers is usually interest plus fees. Savings versus the next-best offer is the difference between the two lowest total-cost results. A zero value can mean only one valid offer is active or two offers have effectively identical total costs.

Monthly cash outflow and fastest payoff

The first-month cash outflow includes the scheduled principal-and-interest payment, any extra monthly payment, and the monthly fee. The final payment may be lower. Lowest monthly outflow is useful for budgeting, but it does not identify the cheapest loan. Fastest payoff shows the number of modeled monthly payments until the balance reaches zero. Extra principal payments can make the actual payoff shorter than the original term.

Interest, fees, total paid, and effective annual cost

Total interest is the sum of monthly interest charges. Total fees combines the upfront charge with monthly fees through payoff. Total paid adds principal, interest, and fees. The fee-adjusted effective annual cost is calculated from the net cash received and the modeled monthly cash outflows using an internal-rate-of-return approach. It can be higher than the note rate when fees are present. This estimate is useful for side-by-side analysis but is not a substitute for a lender’s legally required APR calculation, whose rules and rounding conventions may differ.

Reading the charts and schedule

The repayment-composition chart separates principal, interest, and fees for each active offer. When amounts are equal, the shortest bar generally indicates the lowest cash cost. The balance chart plots the remaining principal after each monthly payment. A steeper line means faster principal reduction. The milestone table exposes exact balances represented by the chart so the graphic is never the only source of information.

The amortization schedule shows payment, principal, interest, fees, and ending balance. In monthly view, interest should generally decline while principal rises for a standard fixed payment. Annual view aggregates the same monthly rows. The last row should end at zero, apart from insignificant floating-point rounding that the model explicitly caps. Download Excel uses the current inputs and the same schedules, so changed assumptions are reflected at click time.

Practical comparison checks

• First compare equal principal amounts and equal terms to isolate rate and fee differences.
• Then test the shortest term whose payment remains realistically affordable.
• Confirm whether quoted rates are fixed, whether fees are financed or paid separately, and whether extra payments are penalty-free.
• Keep an emergency-cash buffer; the mathematically cheapest offer may not be the safest payment for a volatile budget.
• Review the lender’s final disclosure. The Federal Reserve consumer resources provide additional background on borrowing and credit.