What you provide
What you provide
- Current mortgage balance: Outstanding principal.
- Annual interest rate: Nominal annual rate.
- Current monthly payment: Scheduled monthly payment.
- Extra monthly amount: Additional monthly amount applied to the loan.
HOUSING / FINANCE PLANNING
Mortgage Overpayment Calculator
Compare payoff time and interest when a fixed extra amount is added to an existing monthly mortgage payment.
- 01 Calculated in this tab
- 02 Values stay in this browser tab
- 03 Use boundary
Use boundary
Calculation path
Enter the values shown in the form. Nirmion evaluates the displayed formula in your browser and reports the result with supporting metrics.
Calculation path
Each month: interest = balance x annual rate / 12; closing balance = balance + interest - payment.
What you receive
What you receive
- A primary estimate
- Supporting cost or ratio metrics
- The formula, assumptions, and limitations used
Use boundary
Choose the maximum decimal places shown. This does not increase source accuracy.
This is a planning estimate, not a lending approval, tax opinion, valuation, or financial recommendation. Confirm current lender terms, local rules, fees, and professional advice before acting.