Accelerated Biweekly Mortgage Payments: How Much You Save (2026)
Accelerated biweekly payments on a $450,000 mortgage at 4.5% clear it 3.3 years early, saving $45,000 in interest. Plus why regular biweekly saves nothing.
Accelerated biweekly payments take your monthly payment, halve it, and charge that every two weeks. Because there are 26 two-week periods in a year, you make the equivalent of 13 monthly payments instead of 12. On a $450,000 mortgage at 4.5% over 25 years that extra payment shortens the amortization to about 21.7 years and saves roughly $45,000 in interest. Regular biweekly (the monthly payment × 12 ÷ 26) saves almost nothing. It just changes the schedule, not the total.
Figures come from the CostToClose mortgage payment calculator.
Accelerated vs regular: the only distinction that matters
| Metric | Monthly | Regular biweekly | Accelerated biweekly |
|---|---|---|---|
| Payment | $2,491 | $1,150 | $1,245 |
| Paid per year | $29,892 | $29,900 | $32,370 |
| Years to pay off | 25.0 | 25.0 | 21.7 |
| Total interest | $297,188 | $295,821 | $252,118 |
| Interest saved vs monthly | — | $1,367 | $45,070 |
$450,000 at 4.5%, 25-year amortization, computed with the CostToClose calculator, 14 September 2026, assuming the rate holds. Regular biweekly saves a little because interest is charged on a slightly lower balance between payments; accelerated saves a lot because you pay $2,478 more a year.
The same applies to weekly: regular weekly is monthly × 12 ÷ 52 and saves nothing; accelerated weekly is monthly ÷ 4.
Why it works
The extra half-payment each year goes straight to principal. In year one that is $1,245 off a balance of roughly $440,000, which is not much. But every dollar of principal you remove stops accruing interest for the remaining two decades, so the effect compounds: by year ten the accelerated schedule has the balance about $32,000 lower, by year twenty about $81,000.
You can get the same result on a monthly schedule by increasing the payment by one-twelfth ($208 a month here). Most lenders allow a 10% to 20% payment increase a year without penalty, so nothing stops you. Accelerated biweekly is simply the version that matches a biweekly paycheque. The Extra Payment Savings calculator runs that flat-monthly version for your own balance, rate and amortization.
Worked example from the calculator
Buyer with a $556,740 mortgage (a $600,000 house, 10% down, CMHC premium included), 4.49%, 25 years:
| Metric | Monthly | Accelerated biweekly |
|---|---|---|
| Payment | $3,078 | $1,539 |
| Years to pay off | 25.0 | 21.7 |
| Total interest | ≈ $366,750 | ≈ $311,000 |
| Saved | — | ≈ $55,500 and 3.3 years |
What changes the number
- Rate. The higher the rate, the more accelerated payments save: at 6% the same $450,000 mortgage saves about $77,000 and four years.
- Amortization. Longer amortizations save proportionally more, because there is more interest to avoid.
- Rate changes at renewal. The years saved hold up well; the dollar figure moves with each renewal rate.
- Prepayment penalties. None. Switching payment frequency is a prepayment privilege at essentially every lender, changeable at renewal or often mid-term.
When it is not the right move
If you carry credit-card or car-loan debt at higher rates, the extra $2,478 a year does more work there. Pay that down first. If your emergency fund is thin, keep the money liquid instead: a lump-sum prepayment at year end achieves the same result and can be skipped in a bad year.
Frequently asked questions
What is the difference between biweekly and accelerated biweekly?
Regular biweekly is your monthly payment × 12 ÷ 26 — the same annual total, just split into 26 pieces. Accelerated biweekly is the monthly payment ÷ 2, which adds one extra monthly payment a year and is what actually shortens the mortgage.
How many years do accelerated biweekly payments save?
About 3 to 3.5 years on a 25-year amortization at rates between 4% and 5%. On a 30-year amortization, closer to 4.5 years.
Can I switch to accelerated biweekly mid-term?
Usually yes; most lenders let you change payment frequency at any time without penalty. Confirm in your mortgage's prepayment terms.
Is accelerated weekly better than accelerated biweekly?
Marginally. Both make 13 months of payments a year; weekly reduces the balance a few days sooner. The difference is a few hundred dollars over the mortgage.
Does accelerated biweekly change my interest rate?
No. Rate, term and compounding are unchanged. Only the payment amount and frequency change.
Sources
- Financial Consumer Agency of Canada, choosing a mortgage payment frequency — checked 14 Sept 2026
- CostToClose payment engine (semi-annual compounding per Interest Act s. 6) — 14 Sept 2026
This is general information for Canadian home buyers and sellers, checked against the sources listed above on the date shown, and it is not legal, tax, or mortgage advice. Rules and rates change, so confirm current figures with your lawyer or notary, your lender, or the government office that administers the tax before relying on them.