Finance
Cumulative Interest Calculator
Estimate total interest paid over a loan’s life, track interest to date, and see how extra payments change your payoff timeline and cumulative interest.
Total Interest Over Time and Amortization Breakdown
Enter your loan details to calculate payment, cumulative interest, interest to date, and a full amortization table with export.
This tool models a fixed-rate amortizing loan. Payment is calculated from principal, APR, and term unless you set a payment override. Interest is computed each period from the remaining balance, then cumulative interest is the running total.
Interest to date is your cumulative interest from the start through the selected point in time. Use either an As Of Date or an exact number of payments made. If both are provided, Payments Made is used.
| Year | Paid | Interest | Principal | End Balance | Cumulative Interest |
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Extra payments reduce principal faster, which usually reduces total cumulative interest. Choose whether you want to shorten the payoff timeline or keep the original end date and recalculate a smaller payment.
The amortization schedule shows how each payment splits into interest and principal, plus your running cumulative interest. Export CSV to keep a record or compare scenarios.
| # | Date | Payment | Extra | Interest | Principal | Balance | Cumulative Interest |
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| Year | Payments | Paid | Interest | Principal | End Balance | Cumulative Interest |
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