Home & Debt calculator
How much sooner could the mortgage end, and how much interest might extra principal save?
Compare the scheduled mortgage payoff with an extra monthly or one-time principal payment.
Before you calculate
How much sooner could the mortgage end, and how much interest might extra principal save?
An extra mortgage payment changes both the outstanding principal and every later interest charge. This calculator rebuilds the loan month by month, compares the scheduled path with the extra-payment path, and shows the estimated time and interest saved without mixing escrow, property tax, or insurance into the loan math.
Before you act on the number
Use the result to identify which assumption needs verification, then bring that question to the professional helping you make the decision.
Transparent method
Calculate the fixed monthly principal-and-interest payment from the current balance, annual interest rate, and remaining term.
Amortize the scheduled loan monthly by adding interest on the outstanding balance and subtracting the required payment.
Apply any one-time payment directly to principal, add the recurring extra principal each month, and compare the resulting payoff period and total interest with the original schedule.
Common questions
It can when the servicer applies it as an additional principal payment. Confirm the lender’s instructions and review the next statement.
Future monthly interest is calculated on a smaller balance, so more of each later payment goes to principal and the loan can end sooner.
No. The calculated payment is principal and interest only. Taxes, insurance, mortgage insurance, and other escrow items do not reduce the loan balance.
That decision depends on liquidity, risk, taxes, time horizon, other debt, and the value you place on reducing a guaranteed borrowing cost. This tool only calculates the loan path.
Sources
Want the fine print? See sources, methods, and limits.