25 vs 30 Year Amortization in Canada: Real Cost Compared (2026)
A 30-year amortization on a $500,000 mortgage at 4.5% cuts payments $246 a month but adds $77,000 in interest. Who qualifies for 30 years, and when it pays.
On a $500,000 mortgage at 4.5%, a 30-year amortization runs $2,521 a month against $2,767 for 25 years ($246 less), and costs $407,588 in total interest instead of $330,209, about $77,000 more. Thirty years is available to anyone with 20% or more down, and since December 2024 to insured buyers who are first-time buyers or purchasing new construction, at a 0.20% premium surcharge.
Figures come from the CostToClose mortgage payment calculator, using semi-annual compounding as Canadian fixed mortgages require.
What amortization is
Amortization is the total time it takes to pay the mortgage to zero at the current payment. It is not the term, which is the length of your current contract, usually five years. You renew the term several times over one amortization, and each renewal recalculates the payment on the years remaining.
The comparison
| Metric | 25 years | 30 years | Difference |
|---|---|---|---|
| Monthly payment, $500,000 at 4.5% | $2,767 | $2,521 | −$246 (−8.9%) |
| Total interest over the amortization | $330,209 | $407,588 | +$77,379 |
| Balance after the first 5-year term | ≈ $439,000 | ≈ $455,500 | +$16,500 more owing |
Computed with the CostToClose calculator, 14 September 2026, assuming the rate held for the full amortization. Real rates will change at each renewal; the direction of the comparison does not.
The payment relief is real but modest; the interest cost is large because the balance stays higher for longer. Most of the extra $77,000 accrues in years 20 to 30.
Who can choose 30 years
- Uninsured mortgages (20% or more down): 30 years is standard at most lenders; some offer 35.
- Insured mortgages (under 20% down): 25 years, unless you are a first-time buyer or buying a newly built home, in which case 30 years is permitted with a 0.20% premium surcharge. That rule took effect 15 December 2024.
A first-time buyer with 10% down on $600,000 pays $17,820 in premium at 30 years against $16,740 at 25. That's $1,080 for the option.
Worked example from the calculator
First-time buyer, $600,000 resale house, 10% down, 4.49% five-year fixed. Mortgage including premium: $556,740 (25-year) or $557,820 (30-year with surcharge).
| Metric | 25 years | 30 years |
|---|---|---|
| Monthly payment | $3,078 | $2,809 |
| Payment used for the stress test (6.49%) | $3,726 | $3,491 |
| Income needed at 39% GDS (tax $425, heat $210) | $134,185 | $126,943 |
| Interest over full amortization | ≈ $366,750 | ≈ $453,550 |
The 30-year option lets this buyer qualify with about $7,000 less income. That's usually the real reason people choose it, not the lower payment itself. Reproduce this.
When 30 years makes sense
- You need the lower payment to qualify, and you intend to make prepayments or shorten the amortization at renewal once income rises. Most lenders allow 10% to 20% lump-sum prepayments a year without penalty.
- Cash flow matters more than lifetime interest. A rental property is the classic case: the lower payment improves monthly cash flow, and the interest is deductible anyway.
When 25 years is better
- You can carry the payment. The $246 a month in the example buys $77,000 of interest.
- You plan to stay in the mortgage for the long run rather than sell in five years.
The cleanest compromise: take 30 years for the flexibility, set your actual payment at the 25-year amount. You get the same payoff schedule and can drop back to the lower payment if you ever need to.
Who this covers
This is for a standard insured or uninsured residential mortgage from a federally regulated lender, choosing between the two most common amortization lengths. It assumes the rate holds for the comparison; a real mortgage renews every few years at whatever rate is current then, which this comparison doesn't project forward.
What this doesn't include
- What happens at renewal. This compares the two amortizations at one fixed rate for the full term; your actual rate will very likely change at each renewal, which changes both the payment and the interest total.
- Prepayment behaviour. The interest totals shown assume no lump-sum payments or accelerated payment schedule. Most buyers who choose 30 years for flexibility end up paying some of it down faster, which this comparison doesn't model.
- A specific lender's own amortization rules beyond the federal minimum. Some lenders cap uninsured amortizations differently or price 30-year terms with their own rate adjustment.
- Life changes: job loss, disability, a second income arriving. Any of those would change which option actually suits you, beyond the pure interest-cost math shown here.
Questions worth asking a professional
- Ask your lender to confirm you actually qualify for a 30-year insured amortization before assuming it. It's restricted to first-time buyers and new-construction buyers only.
- Ask about prepayment privileges specifically: how much you can pay down each year without penalty, and whether that changes your amortization or just your balance.
- If you're choosing 30 years for cash-flow flexibility, ask whether your lender lets you increase your payment later without re-qualifying.
- Ask what your payment would look like today if you shortened to 25 years at renewal, as a reference point for the "take 30, pay like 25" strategy mentioned above.
Frequently asked questions
Can a first-time buyer get a 30-year mortgage in Canada with less than 20% down?
Yes, since 15 December 2024. Insured 30-year amortizations are available to first-time buyers and to any buyer of a newly built home, with a 0.20% surcharge on the insurance premium.
How much does a 30-year amortization lower the monthly payment?
About 9% at current rates. On $500,000 at 4.5% it is $246 a month less than 25 years.
How much more interest does a 30-year amortization cost?
On $500,000 at 4.5%, about $77,000 more over the life of the mortgage, assuming the rate does not change.
Can I shorten my amortization later?
Yes. At renewal you can pick a shorter amortization, and most lenders allow annual lump-sum and payment-increase prepayments that shorten it without penalty.
Does a longer amortization help with the stress test?
Yes. A 30-year amortization lowers the qualifying payment by roughly 9%, which raises the mortgage you qualify for by a similar amount.
Sources
- Department of Finance Canada, mortgage rule changes: 30-year insured amortizations (effective 15 December 2024) — checked 14 Sept 2026
- CMHC, mortgage loan insurance premiums and amortization surcharge — checked 14 Sept 2026
- Financial Consumer Agency of Canada, amortization period — checked 14 Sept 2026
This guide gives general information for Canadian home buyers and sellers, checked against the sources listed above on the date shown. It is not legal, tax, or mortgage advice. Because rules and rates change, confirm current figures with your lawyer or notary, your lender, or the government office that administers the tax before relying on them.