HousingKit

Mortgage Amortization Calculator Month by month

Generate a payment schedule with principal, interest, and remaining balance. Add extra monthly payments to test payoff acceleration.

Enter values and run calculation.

How to interpret this

Early payments are interest-heavy and principal-light. Extra monthly payments usually reduce total interest more than one-time late lump sums.

Related tools: Mortgage Calculator and Refinance Break-Even Calculator. Related guide: Refinance Break-Even Guide.