Calculation method
Compares the scheduled loan with a monthly principal-and-interest payment increased by the extra amount. Both are simulated month by month.
Mortgages · General formulas
Extra Mortgage Payment Calculator
Estimate potential time and interest savings from paying extra principal. Use the example values or enter your own numbers to explore an estimate.
Currency formatting only—not an exchange-rate conversion. No country-specific tax or government rules are applied.
Your results
See a clear estimate
Enter your details to see a personalized calculation, a simple projection, and the assumptions behind it.
Free to use
No sign-up required
Device saving only when requested
FREE TOOLS · NO ACCOUNT
Compare, keep and export
Calculate first to compare a snapshot or export your current results. No values are sent to our server.
The PDF includes active input values and option labels, results, sources, model assumptions, and the schedule when available. Schedule periods follow the model: years, months, or actual payments.
Up to three comparison snapshots
Optional device-only storage
Share assumptions, never dollar amounts
Links include eligible rate, term or frequency assumptions only. Dollar amounts are never included. Recipients must enter their own amounts; the link will not reproduce your full financial scenario.
Assumptions & limits
- Extra payment goes directly to principal.
- No prepayment penalties or lender-specific rules.
- Basis: User-entered values.
- Basis: Standard fixed-payment and time-value-of-money formulas.
- Basis: https://www.canada.ca/en/financial-consumer-agency/services/mortgages/choose-mortgage.html.
- Basis: https://itools-ioutils.fcac-acfc.gc.ca/MC-CH/MortgageCalculator.aspx.
Source/rule review year: Not applicable — general mathematical model.
EXTRA-PAYMENT WORKED EXAMPLE
How does an extra payment change payoff?
This fictional general-formula example starts with a $320,000 mortgage at 5.25% nominal annual interest compounded monthly, a 25-year amortization, and $250 extra toward principal each month.
| Part | Item | Value |
|---|---|---|
| Input | Mortgage amount | USD 320,000.00 |
| Input | Annual interest rate | 5.25 % |
| Input | Nominal mortgage rate compounding convention | Monthly nominal compounding (rate ÷ 12 for monthly payments) |
| Input | Amortization period | 25 years |
| Input | Extra monthly payment | USD 250.00 per month |
| Input | Monthly property taxes | USD 0.00 |
| Input | Monthly home insurance | USD 0.00 |
| Input | Monthly condo or HOA fees | USD 0.00 |
| Input | Other monthly ownership costs | USD 0.00 |
| Result | New monthly payment | US$2,167.59 |
| Result | Payoff time with extra | 19 yr 10 mo |
| Result | Time saved | 5 yr 2 mo |
| Result | Estimated interest saved | US$59,819.82 |
| Result | Monthly principal and interest (loan only) | US$1,917.59 |
| Result | Monthly property taxes | US$0.00 |
| Result | Monthly home insurance | US$0.00 |
| Result | Monthly condo or HOA fees | US$0.00 |
| Result | Other monthly ownership costs | US$0.00 |
| Result | Entered monthly ownership costs | US$0.00 |
| Result | Monthly housing outflow before extra principal | US$1,917.59 |
| Result | Monthly housing outflow with extra principal | US$2,167.59 |
How to interpret it
The calculator compares a baseline schedule with one that applies the entered extra amount to principal monthly while the regular principal-and-interest payment stays constant. The result is a model of this selected schedule, not a lender prepayment quote. The separate monthly ownership-cost fields are set to zero in this worked example and do not alter principal-and-interest or payoff math.
Limits of this example
- The example explicitly selects monthly nominal compounding. The tool also offers Canadian semiannual nominal compounding; this choice is separate from currency. Amortization is not a Canadian renewal term.
- The payoff calculation excludes ownership costs, fees, prepayment limits and penalties. Entered ownership costs are shown separately as monthly cash outflows. Principal and interest are not total housing costs.
Possible next steps
READ THE METHOD
How mortgage amortization works Want the mechanics before comparing scenarios?