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Extra Mortgage Payment Calculator

See how extra monthly principal payments could reduce interest and shorten a mortgage.

Enter your assumptions

Change a number. Your estimate updates automatically.

Currency changes formatting only; no exchange conversion.

Use your own assumptions. Review the method and exclusions below.

Your estimated future balance
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Projection over time

Assumes a fixed rate and unchanged payments. Fees and new borrowing are excluded. Actual lender schedules may differ.

View yearly breakdown
Year-end projections (rounded for display)

How this tool works

The model first computes the regular payment from the remaining principal, rate, and term. It then runs two amortization schedules: one with the regular payment and one with your added monthly principal payment.

Try an example

Try an extra payment of 200 per month. Compare interest paid and the estimated payoff time with the regular schedule.

Questions & assumptions

What does the payment exclude?

The result includes principal and interest only. It excludes property taxes, insurance, fees, and prepayment penalties. Confirm how your servicer applies extra payments.

Can I export the calculation?

Yes. Download CSV includes inputs and projections. You can also print the results.

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