Property ownership
Mortgage extra payment savings
Compare payoff time and total interest with and without supplied extra principal payments.
Your inputs
Complete the fields for your selected method. Zero means intentionally zero, not unknown. Currency selection labels amounts; it does not convert exchange rates.
How this calculation works
interest[t]=balance[t]*monthly rate; payment=min(scheduled+extra,balance+interest); next balance=balance+interest-payment.
Fixed nominal annual rate divided by twelve; payments at month end. Extra payment begins in month one. Display rounding does not change internal balances.
What information do I need?
Use records for the same job, equipment or accounting period. Only the fields for your selected entry method are required. An unknown amount is not zero.
Input definitions and where to find them
- Current loan principal (selected currency): CURRENT outstanding principal from statement, not original borrowing.
- Nominal annual interest rate (%): Fixed nominal annual rate, not fee-inclusive APR.
- Remaining amortization term (months): Remaining amortization months at that rate.
- Extra principal each month (selected currency): Use matching records or a clearly identified owner assumption for extra principal each month, in the displayed unit and the stated row/period scope.
Use the Where to find this value controls beside the inputs for available work-it-out helpers. Estimates remain your assumptions; a helper does not verify the source figures.
Worked example
Example amounts use US dollars (USD).
Example answer: Scheduled monthly payment is $1,332.25 for the illustrative inputs below.
Example inputs
- Current loan principal: $120,000.00
- Nominal annual interest rate: 6.00 %
- Remaining amortization term: 120 months
- Extra principal each month: $200.00
- Scheduled monthly payment
- $1,332.25
- Baseline total interest
- $39,869.52
- With-extra total interest
- $32,653.78
- Interest saved
- $7,215.75
- Months saved
- 20 months
- With-extra payoff month
- 100 month
- Unrounded internal amortization; final payment is capped. No fees, escrow or prepayment-rule interpretation.
These illustrative values are not recommended rates or industry averages. Replace every example input with your own figures.
Use the result well
Compare payoff time and total interest with and without supplied extra principal payments.
Keep inputs on the same scope and time basis. Calculations retain precision internally; displayed values generally round to two decimal places, with extra precision for very small values and whole-unit rounding where required. Economic comparisons describe your supplied assumptions and do not guarantee future results.
This tool provides business arithmetic. It does not approve engineering designs, establish legal or tax treatment, select equipment or certify safe operating conditions.