Mortgage Prepayment Calculator

Debt & Financing

Blend recurring extra payments and one-off lump sums to test mortgage acceleration strategies.

Enter the values you know. Required fields should be completed first, and optional fields can be left blank if they do not apply to your situation.

Original principal Required

Annual interest rate % Required

Term years Required

Monthly payment Optional Optional. Leave blank to let the calculator derive the scheduled payment.

Extra monthly payment Required

Lump-sum payment Required

Lump-sum month Required

First repayment date Optional Optional. Add repayment dates to both schedules.

Calculating...

The top cards show the most important answers first. Detailed schedules, scenario tables, and supporting notes appear underneath for deeper review.