Mortgage Extra Payment Calculator

How to use this calculator

Enter the current principal balance, mortgage rate, years remaining, and planned extra monthly principal. The tool compares the scheduled loan with the accelerated payoff scenario.

When this calculator is useful

• Comparing extra-payment scenarios before changing autopay
• Comparing prepayment with other savings goals
• Estimating interest savings before changing autopay

Important limitations

Confirm that your servicer applies extra money to principal and check for prepayment restrictions. Taxes, insurance, escrow, and opportunity cost are not included.

For best results, run at least three cases: a conservative case, a middle case, and a stretch case. If a small change in inputs creates a big change in the answer, that is a sign the decision may be sensitive to rates, fees, timing, or market performance.