Free calculator · Paying Off Faster
Biweekly vs Monthly Mortgage Calculator
Compare a monthly payment with accelerated bi-weekly payments and see the interest saved and years shaved off the mortgage.
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| Measure | Monthly | Accelerated bi-weekly |
|---|---|---|
| Payment | — | — |
Estimates only. Results are not a quote, pre-approval, or approval. Confirm payment options with your lender.
How this is calculated
The monthly payment uses the Canadian fixed-rate convention, where the annual rate compounds semi-annually. The effective monthly rate is i = (1 + annual rate ÷ 2)1/6 − 1 and the payment is P = L × i ÷ (1 − (1 + i)−n) over n = amortization in months. The accelerated bi-weekly payment is simply half of that monthly payment, taken every two weeks. Because there are 26 bi-weekly periods in a year, that equals 13 monthly payments a year instead of 12, and the extra payment goes straight at the principal.
The bi-weekly schedule is then simulated period by period. The effective bi-weekly rate is (1 + annual rate ÷ 2)1/13 − 1, applied to the declining balance until it reaches zero. Comparing the two payoff dates gives the interest saved and the time shaved off the amortization. The tool caps the simulation at a generous number of periods so a very low payment can never loop forever.
A few points worth knowing:
- Accelerated bi-weekly means half the monthly payment each period. A plain bi-weekly plan, which is the monthly payment times 12 divided by 26, pays off at almost the same time as monthly.
- Switching frequency usually does not trigger a penalty, but confirm it with your lender and check the fine print of your mortgage.
- The comparison assumes the rate stays fixed for the whole amortization and ignores any term renewals, prepayment limits, or fees.
All figures are estimates for planning only, not a quote, pre-approval, or approval. Confirm the available payment frequencies and any conditions with your lender.