Use this loan calculator to see a monthly payment, total interest, and an estimated payoff date for a fixed-rate loan. Start with the loan amount, annual interest rate, and term in months. Open the extra-payment options to add a recurring amount or a one-time principal payment. The result compares that plan with the original schedule, so you can see the interest saved and payments avoided. Open the full amortization schedule to review each payment, or download it as a CSV. Replace the source-based starting values with the terms of your own loan.
Worked formula check
The inputs come from CFPB installment-loan sample inputs. This check uses regular monthly periods, excludes the sample's odd first period and other charges, and calculates the outputs with the formula below. It is not a lender offer.
| Input or result | Value |
|---|---|
| Source loan amount | $5,000.00 |
| Source annual interest rate | 12% |
| Source term | 2 years, converted to 24 months |
| Calculated monthly payment | $235.37 |
| Calculated total interest | $648.82 |
| Calculated total payments | $5,648.82 |
Choose the inputs that match your loan
Enter the balance that will accrue interest, rather than the amount of cash you need after fees. Use the annual contract interest rate for the payment calculation. If your paperwork also lists an APR, keep that figure for a cost comparison; the APR tool explains how a fee can affect it. Enter the number of monthly payments in the term field. The default values are calculation inputs taken from a CFPB installment-loan sample, not an advertised loan offer.
Read the extra-payment comparison
An extra monthly payment is added to every scheduled payment, starting with the first one. A one-time payment is added in the payment month you select. Both reduce principal after that month's interest is calculated. The final payment is capped at the amount still owed, so an oversized extra payment cannot produce a negative balance. The interest-saved result compares the two modeled schedules at the same interest rate. Ask the lender how extra funds will be applied before using the result as a payment plan.
How it works
r = annual interest rate (%) / 100 / 12
P is the interest-bearing balance, n is the number of monthly payments, r is the monthly rate, and A is the scheduled payment. At a zero interest rate, A = P / n. Each month, interest = opening balance * r; principal = payment - interest; closing balance = opening balance - principal.
This is the regular-payment form of the actuarial relationship in CFPB actuarial formulas, Appendix J. The schedule retains full precision internally and rounds amounts only for display. The model uses a fixed rate and equal monthly periods. It excludes daily accrual, irregular first periods, missed payments, and prepayment charges.
Frequently asked questions
How do I calculate a monthly loan payment?
Enter the loan amount, annual contract interest rate, and number of monthly payments. The calculator uses the fixed-payment formula below and shows principal and interest without fees.
Can I use this loan calculator with extra payments?
Yes. Open Extra payments and dates to add a recurring monthly amount or a one-time payment in a selected payment month. The scheduled payment stays fixed while the balance falls faster.
Where is the full loan amortization schedule?
Select Full amortization schedule below the result. It lists the payment, interest, principal, and remaining balance for every modeled month. You can download the same rows as CSV.
Does the calculator use APR or the interest rate?
Use the annual contract interest rate for the payment. APR can include finance fees. The APR vs interest rate calculator models a fee withheld from your loan proceeds.
How is early payoff interest saved calculated?
The tool subtracts interest under your extra-payment plan from interest under the original schedule. Both schedules use the same starting balance and rate, with equal monthly interest periods.
Can I compare personal loans with this calculator?
Use the personal loan tool for a payment and withheld upfront fee. Use the loan comparison tool to put separate offers beside each other, or the consolidation tool to compare existing debts with a new loan.