Accelerated Payment Calculator

What the Accelerated Payment Calculator does

This calculator lays out all six Canadian mortgage payment frequencies side by side — monthly, semi-monthly, bi-weekly, accelerated bi-weekly, weekly and accelerated weekly — and shows the true payment, actual payoff period and total interest for each one, at your rate and amortization.

Every non-monthly figure here is derived the way Canadian lenders actually derive it: from the monthly payment first, never solved independently. For the two accelerated frequencies, the shortened amortization is solved directly rather than assumed, because the real payoff date does not fall on a clean number of years.

• Payment amount at all six frequencies
• Actual payoff period for each, correctly shortened for the two accelerated options
• Total interest paid over the life of the mortgage at each frequency
• Interest saved and time saved switching between your current and a target frequency
• The honest cost side: how much more you actually pay per year to get that saving

The key variables that move the answer — and how lenders treat them

Two things do all the work here, and lenders look at both very differently from how a borrower experiences them.

• Payment frequency — this changes nothing about your rate and everything about your payoff date. Accelerated bi-weekly pays half the monthly amount 26 times a year, which is mathematically 13 monthly payments instead of 12 — one extra full payment a year, applied entirely to principal. Non-accelerated bi-weekly and semi-monthly simply repackage the same annual amount into more, smaller payments and save comparatively little.
• Mortgage amount and rate — these set the monthly baseline every other frequency is derived from. A larger mortgage or a higher rate means accelerated payments save a larger dollar amount, though the shape of the saving — roughly three to four years off a 25-year amortization — stays fairly consistent across most typical mortgage sizes.
• Lenders qualify you on the monthly-equivalent payment regardless of the frequency you actually choose, so switching frequency does not change how much mortgage you can be approved for. It only changes how quickly you pay off what you already have.

How payment frequencies are actually calculated in Canada

The monthly payment is calculated first, using the standard Canadian formula with semi-annual compounding for a fixed rate: P × i ÷ (1 − (1 + i)^−N), where i is the periodic rate implied by the compounding convention and N is amortYears × 12.

Every other frequency is then derived from that monthly figure, not solved independently. Semi-monthly is simply half the monthly payment, paid 24 times a year. Non-accelerated bi-weekly and weekly scale the annual total (monthly × 12) down to the new number of periods, so the annual amount paid stays the same as monthly — these do not accelerate payoff meaningfully. The two accelerated frequencies keep the monthly payment amount itself but split it in half (bi-weekly, 26 times a year) or in quarter (weekly, 52 times a year), which raises the annual amount paid by roughly one extra monthly payment.

Because the accelerated payment no longer matches what a clean N-period amortization schedule would produce, the true number of periods to reach zero balance is solved directly rather than assumed — a payment that is even slightly more than the interest accruing each period will pay off strictly faster than dividing the stated amortization by the new frequency would suggest.

• Monthly baseline: P × i ÷ (1 − (1 + i)^−N)
• Semi-monthly: monthly ÷ 2, 24 times a year
• Bi-weekly / weekly (non-accelerated): monthly × 12 ÷ n, same annual total as monthly
• Accelerated bi-weekly: monthly ÷ 2, 26 times a year — 13 monthly payments' worth annually
• Accelerated weekly: monthly ÷ 4, 52 times a year — same effect as accelerated bi-weekly
• Actual payoff period: solved directly from the payment and periodic rate, never assumed

What you get from this calculator, and what lenders actually offer

Nearly every Canadian lender offers all six frequencies at no cost, and most allow you to change frequency at any time, not just at renewal. That makes this one of the very few mortgage decisions that costs nothing to implement and can be reversed if your cash flow changes.

• Interest saved — the headline figure, and a genuine saving from paying down principal faster, not a lender promotion or a trick
• Time saved — typically three to four years off a 25-year amortization when switching from monthly to accelerated bi-weekly
• Extra paid per year — the honest other half of the story: the saving is funded by paying roughly one extra monthly payment's worth annually
• Payment at each frequency — useful for matching your mortgage payment to a bi-weekly or weekly pay cheque, independent of whether you choose the accelerated version

Using your results well

If your budget can absorb it, accelerated bi-weekly is usually the highest-value, lowest-effort change you can make to a mortgage — it requires no renegotiation, no penalty and no change in rate, and most lenders let you switch to it whenever you like. Compare it against a plain bi-weekly or semi-monthly frequency in this calculator to see how much of the benefit actually comes from the acceleration itself, rather than just the more frequent payment date.

What this calculator does not do is model a change in rate, term or lender — it holds those constant and isolates the effect of frequency alone. It also assumes you keep paying every scheduled payment on time for the full period; missed or reduced payments would change the actual payoff date.

• Match your payment frequency to your pay cheque, then decide separately whether to accelerate it
• Confirm with your lender whether a frequency change is free and how much notice it needs
• Combine this with a lump-sum prepayment calculator for the two most effective free ways to pay off a mortgage faster
• Remember the saving is fully funded by paying more each year, not by a lower rate

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