Loan calculator
Calculate the monthly payment, total interest and complete amortization schedule for a fixed-rate loan. Add a recurring overpayment to see how much time and modeled interest it could save.
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The scheduled payment uses the standard annuity formula for equal monthly installments. Interest accrues monthly on the remaining principal.
Principal and interest by month
| Payment | Total payment | Principal | Interest | Extra principal | Ending balance |
|---|
The final payment can be smaller than the regular amount. Downloaded values use two decimal places and the selected currency is for display only.
How to read the result
Interest is calculated from the opening balance each month. The rest of the payment reduces principal, so the interest portion normally falls as the balance declines. A lower scheduled payment can still mean a higher total cost when the loan lasts longer.
Worked example
For a $25,000 loan at a fixed 7.5% nominal annual rate over five years, the modeled scheduled payment is $500.95 and total interest is $5,056.92. Adding $100 every month repays the model in 49 months instead of 60 and reduces modeled interest to $4,043.31.
Those figures assume monthly compounding, payments at month end, no fees and every overpayment going directly to principal.
Method and limitations
The calculator excludes origination charges, insurance, taxes, grace periods, variable rates, payment holidays, irregular payment dates and contractual penalties. Compare APR or APRC and the contract's total borrowing cost as well as the nominal rate used here.
Consumer Financial Protection Bureau — How amortization divides principal and interest
Bank of England — Borrowing calculator
European Central Bank — Bank interest rate methodology