Amortization Schedule Calculator
Build the full monthly period table for a fixed-rate balance. Each row splits the payment into interest and principal and shows the remaining balance; the totals row reconciles every cent.
The table contains every modeled month, up to 360 rows. No rows are omitted. The last payment can be slightly larger or smaller than the regular amount because of cent rounding.
Free to use, with no sign up. Calculations run in your browser; entries are not uploaded.
Result
P = entered principal − down payment; i = annualRatePercent / 1200; n = term in months. Regular payment M = P × i / [1 − (1 + i)^(−n)]. At 0%, M = P / n. Monthly interest = previous balance × i; principal repaid = actual payment − interest; new balance = previous balance − principal repaid. Total payments = P + total interest.
Primary source: OpenStax Principles of Finance: loan amortization, the present value of an ordinary annuity rearranged for monthly payment. This calculator uses nearest-cent, half-up rounding for both payments and monthly interest.
Worked example: For $100 at 12% annually over 3 months, the rounded formula payment is $34.00. Row one: $1.00 interest, $33.00 principal, $67.00 balance. Row two: $0.67 interest, $33.33 principal, $33.67 balance. Row three clears $33.67 plus $0.34 interest with $34.01. Payments total $102.01 = $100.00 principal + $2.01 interest. For $100 at 0% over 3 months, payments are $33.33, $33.33 and $33.34.
Monthly payment table
Model bounds: positive financed balance; monetary inputs up to $100,000,000 with at most two decimal places; annual rate from 0% to 100% with at most six decimal places; 1–360 whole months. All periods are equal months, with the first payment after one month. The schedule has at most 360 rows. Payments stop at zero balance. A formula payment below one cent becomes one cent; the final period clears any rounding residue. Totals exclude the down payment and include loan payments only. Fees, penalties and changing rates are excluded.
How to use this tool
Enter amounts in USD, the fixed nominal annual interest rate as a percentage and a whole-month term. Select Calculate to update the payment, totals and period table. Enter zero for no extra monthly payment.
Frequently asked questions
How are cents and the final payment handled?
Money inputs accept at most two decimal places. Payment and each monthly interest charge round to the nearest cent, with exact half cents rounded upward. The last payment clears the remaining balance and interest, so it may differ from the regular payment.
What happens at a zero interest rate?
The regular payment is financed principal divided by the entered months, rounded to cents with a one-cent minimum. Each payment reduces principal only, and the last payment clears the remaining cents.
How do extra monthly payments affect the schedule?
The regular payment is computed from the financed principal, rate and original entered term. The extra amount is added each month and reduces the balance sooner. Payments stop when the balance reaches zero; a final short payment includes only the remaining balance and interest.