Enter a loan balance, a fixed annual interest rate and the number of monthly payments to estimate repayment. Look at total interest as well as the monthly amount. A longer term can spread the payment while increasing the overall cost.
This calculator models equal monthly payments starting one month after funding. It uses US dollars and a monthly interest rate of the annual rate divided by 12. Fees, variable rates, late payments and payment holidays require separate treatment.
Calculate a fixed monthly payment
Use the balance and rate from the actual terms
Loan principal is the balance on which this model calculates interest. Include financed charges in that balance once. Annual interest rate is the contractual rate, which may differ from the quoted APR. Term is the number of payments: a three-year monthly loan has 36 payments.
Ask whether the rate stays fixed and how interest accrues. Personal installment-loan terms can vary; the CFPB personal-loan guide explains the role of rates, fees and repayment obligations. This model suits a fixed, fully amortizing loan. Credit cards, balloon payments and income-based student-loan arrangements need their own calculations.
Separate the loan balance from cash received
A fee may be paid separately, deducted from what you receive or added to what you owe. Record its treatment before comparing offers. These fictional examples all begin with a $10,000 amount and a $500 charge:
| Fee treatment | Principal entered | Cash available / separate cost |
|---|---|---|
| Deducted from proceeds | $10,000 | $9,500 received; repay a $10,000 balance plus interest. |
| Added to principal | $10,500 | $10,000 received; interest is modeled on $10,500. |
| Paid separately | $10,000 | $10,000 received and $500 paid outside the loan. |
The result's total loan payments includes principal and modeled interest only. Add separately paid fees when comparing cash outflows; avoid adding a financed fee again if it is already in the principal. For a deducted fee, compare payments with the lower net proceeds. The model does not derive APR from these cash flows.
For a home loan, the CFPB explanation of interest rate and APR describes how APR incorporates additional borrowing charges. Use the lender's actual disclosures for APR, then use the contractual interest rate here to model payments. Keep the loan type, term and fee treatment consistent across comparisons.
Read the amortization schedule
Each month, this model multiplies the opening balance by the monthly rate to calculate interest. The rest of the payment reduces principal. The following month begins with that smaller balance. It rounds interest and scheduled payments to cents and adjusts the final payment to clear the balance.
For a positive monthly rate r, a principal P and n payments, the unrounded payment is P × r ÷ (1 − (1 + r)−n). At a zero rate it is P ÷ n. The schedule lets you inspect that relationship rather than treating the monthly number as a complete explanation.
A lender may use daily accrual, different rounding or an irregular first payment date, so its exact schedule may differ. Ask for an explanation if a quoted payment differs materially. Compare principal, rate, dates, payment count and financed fees first.
Compare a manageable payment with the full cost
- Save the quoted principal, net proceeds, contractual rate, APR and every fee.
- Run one term, then change only the term to see its effect on payment and interest.
- Check whether the payment fits after essential expenses and a cash reserve.
- Review the contract for variable rates, prepayment terms and charges outside the modeled schedule.
For purchase-specific inputs, use the car loan calculator or mortgage and housing-cost calculator. For existing balances, start with a debt repayment plan. Treat an unsolicited approval promise using the loan-offer verification guide.
US guidance reviewed October 6, 2026. Explore loans, credit and debt guides.