Meta description: Breaking a Canadian mortgage early costs a penalty: 3 months' interest or IRD. See worked dollar examples, the break-even math, and porting.
Breaking a fixed-rate mortgage early in Canada almost always triggers a penalty. That penalty can be a few thousand dollars or a five-figure bill, and which one you get depends on your mortgage type, your remaining term, and where rates have gone since you signed. The good news: the math is knowable, and sometimes breaking out still saves you money.
Canadian lenders use two formulas for fixed-rate mortgages, and they charge you the higher of the two:
1. Three months' interest. This is simple. Take your annual interest rate, divide by 12, multiply by 3, and multiply by your outstanding balance. On a $500,000 balance at 4.89%:
$500,000 x 4.89% / 12 x 3 = $6,113
This penalty barely changes over time. It is the same whether you have four years left or four months left.
2. Interest Rate Differential (IRD). This is the one that can sting. The IRD measures how much money the lender loses when they re-lend your money at today's lower rate. The simplified formula most Big 5 banks use:
(Your contract rate minus the lender's current posted rate for a term close to what you have left) x outstanding balance x years remaining.
Here is a worked example. You locked a 5-year fixed at 4.89% two years ago. Your balance is $500,000 and you have 3 years left. The lender's current posted rate for a 3-year term is 4.09%:
(4.89% - 4.09%) x $500,000 x 3 years = 0.80% x $500,000 x 3 = $12,000
The lender takes the higher number, so your penalty is $12,000, not $6,113.
The details vary by lender. Some use posted rates minus a discount; others use discounted rates directly. Monolines and credit unions often have fairer IRD formulas than the Big 5. Before you do anything, ask your lender for the actual penalty quote in writing. It is free to ask, and you should ask more than once, because the number moves as posted rates move.
If you have a variable-rate mortgage, the penalty is almost always just three months' interest, no IRD. On that same $500,000 balance at, say, 4.25%:
$500,000 x 4.25% / 12 x 3 = $5,313
That is a predictable, modest number, and it is why breaking a variable mortgage for a better deal is a much easier decision.
The only question that matters: does the interest you save exceed the penalty plus costs? Work it through step by step.
Take a borrower with a $450,000 balance, 4 years left on a 5-year fixed at 5.19%, and a quoted penalty of $13,500 (IRD, because rates have fallen since signing). A new lender offers 4.19% for the remaining 4 years. Other costs: roughly $500 in appraisal and legal fees, though many lenders cover switching costs on a straight transfer.
Interest savings: the 1.00% rate drop on $450,000 saves roughly $375 per month in interest at the start, declining slowly as the balance shrinks. Over 4 years, total savings land around $16,000.
$16,000 in savings minus $13,500 penalty minus $500 costs = about $2,000 ahead. It pays off, but barely. The break-even point is around month 37 of the 48-month window, meaning you are betting nothing better comes along.
Now flip it: if the rate drop were 1.50% instead of 1.00%, savings would be around $24,000 against the same $13,500 penalty. That is a clear win, with break-even around month 27. The lesson: the bigger the rate gap and the longer the remaining term, the more breaking out pays. With less than 2 years left, the penalty is usually too large relative to the remaining savings unless rates have fallen dramatically.
Two situations where breaking early is often worth it even with a painful penalty:
If you are breaking because you are buying a new home, porting lets you transfer your current mortgage, with its rate and terms, to the new property instead of paying the penalty. Most Big 5 banks allow 30 to 90 days between selling and buying to complete the port.
Porting makes sense when your existing rate is competitive with current offers. If your rate is 4.50% and the market is at 4.19%, porting keeps you on the higher rate for the rest of the term, so do the math. If you need a bigger mortgage for the new place, lenders offer a blend and extend: your old balance keeps the old rate, the new money gets today's rate, and everything is combined into one new rate.
Ask about porting before you sell. Once the mortgage is discharged, the option is gone.
Penalty quotes from your lender are free and non-binding. Ask for:
Then run the break-even: monthly savings times months remaining, minus the penalty and any fees. If the result is clearly positive with room to spare, breaking out is worth it. If it is close, waiting until renewal is usually the safer play, especially since penalties shrink as you get closer to maturity.
Fixed-rate penalties are the higher of three months' interest or the IRD, and the IRD can be five figures when rates have dropped. Variable-rate penalties are only three months' interest. Breaking out pays off when the rate gap is wide, the remaining term is long, and the savings clear the penalty with room to spare.
If you are approaching renewal, you do not need to break at all. Check what rates other Canadians are actually getting with the crowdsourced live rate reports on fiveyear.ca, and run your offer through the renewal checker to see where you land.