Porting a mortgage means transferring your existing rate and term to a new property instead of breaking your current mortgage and starting fresh. You avoid the break penalty on the ported portion, but you still have to requalify for the new loan, and if you need more money to buy the new home, you end up with a blended rate that mixes your old rate with today’s rate on the extra funds.
Most fixed mortgages in Canada are portable, but the rules, timelines, and blend math all vary by lender. Here is how it actually works, what it saves you, and when breaking your mortgage outright is the better move.
What Does It Mean to Port a Mortgage?
Porting means your current lender lets you move your existing mortgage, at its existing rate and remaining term, onto a new property when you sell one home and buy another. You are not opening a new mortgage from scratch. You are carrying the old one forward.
This matters most when your existing rate is well below what is currently available. If you locked in a fixed rate two or three years ago and the market has moved higher since, porting protects that rate instead of forcing you to accept today’s pricing on your full new balance.
Not every mortgage is portable. Most major bank and monoline fixed mortgages are, but variable-rate mortgages, some no-frills or discounted products, and mortgages with certain lenders may have limited or no porting privilege. Check your current mortgage commitment or ask your lender directly before assuming porting is available.
A ported mortgage carries your existing rate and term to a new property, keeping the original contract in place instead of replacing it.
How Porting Avoids the Break Penalty
Porting avoids a break penalty because you are not actually breaking the mortgage, you are moving it. When you sell your home and pay out a mortgage before its maturity date, most lenders charge either three months’ interest or an interest rate differential (IRD) penalty, whichever is higher on a fixed mortgage. That penalty can run into the thousands of dollars depending on your balance, your rate, and how much time is left on your term.
Porting sidesteps that cost on the portion you carry forward. Most lenders give you a window, commonly somewhere between a few days and about 30 days between selling your old home and closing on the new one, to complete the port without triggering the penalty. That window length varies by lender, so confirm the exact number with your specific lender before you rely on it.
If your closing dates do not line up (you sell before you buy, or buy before you sell), a short-term bridge financing arrangement can cover the gap without breaking the port. For the full mechanics of how penalties are calculated in the first place, including the three-months-interest and IRD formulas, see our guide to how mortgage penalty calculations work.
Porting works because you are transferring an existing contract rather than terminating it, which is exactly what avoids the penalty a break would trigger.
You Still Have to Requalify
Porting your rate does not mean skipping the approval process. Because you are taking on a new property, most lenders require you to requalify under current income, credit, and debt-ratio rules, including the mortgage stress test, even though the rate itself is protected.
This surprises a lot of homeowners who assume their existing approval just carries over. It does not. If your income has dropped, your credit has weakened, or your debt load has grown since your last mortgage, you can be declined for a port even while keeping the exact same rate you already have.
The upside is that a strong file usually ports through cleanly. If your financial picture is stable or improved since your last approval, requalifying is often a formality rather than an obstacle.
Porting protects your rate, but it does not protect you from having to prove, all over again, that you qualify for the loan.
Buying a Bigger Home? How the Blended Rate Works
If your new home costs more than the payout on your old mortgage, you will need additional funds, and those funds get priced at a blended rate rather than your old rate. The blend combines your existing rate on the ported balance with the current market rate on the new money, weighted by how much of each you are borrowing.
Here is an illustrative example, with the numbers labelled clearly so you can see exactly how a blend is built.
| Component | Balance | Rate | Balance × Rate |
|---|---|---|---|
| Ported (existing) mortgage | $300,000 | 3.00% | $9,000 |
| New money for the bigger home | $150,000 | 5.00% | $7,500 |
| Total / blended | $450,000 | 3.67% | $16,500 |
In this illustrative scenario, a $300,000 mortgage at 3.00% is ported alongside $150,000 of new money at 5.00% (both rates chosen only to demonstrate the arithmetic, not as a quote). The blended rate on the full $450,000 works out to roughly 3.67%, well below the 5.00% you would pay if you refinanced the entire amount at today’s rate, and above the 3.00% you were paying before.
Lenders do not all calculate a blend the same way. Some weight it strictly by dollar amount as shown above, others factor in the remaining term of each portion, and some will only blend up to the remaining term of your existing mortgage rather than extending it. Confirm the exact blend formula with your specific lender before you rely on a number, since this genuinely varies.
A blended rate averages your old rate and today’s rate across your combined balance, and the exact formula for that average varies by lender.
Port vs Break-and-Refinance: How to Decide
The right choice depends on how much your old rate beats today’s market, how large your penalty would be, and how much new money you need. Use this as a starting framework, not a final answer, since your specific numbers will move it one way or the other.
| Situation | Porting usually wins | Breaking and refinancing usually wins |
|---|---|---|
| Gap between your rate and today’s rate | Your existing rate is meaningfully below current rates | Rates have dropped since you locked in, or are close to your rate |
| New money needed | Small relative to your existing balance | Large, so the blend would sit close to today’s rate anyway |
| Penalty size | Penalty on your current balance would be significant | Penalty is modest (early in a variable term, or a small balance left) |
| Timeline flexibility | Closings can be arranged inside the lender’s port window | You need speed or flexibility a port window will not allow |
| Lender fit | You are happy staying with your current lender | A different lender offers meaningfully better terms or products |
Run both numbers before deciding. A broker can calculate your actual penalty, your actual blend, and a fully refinanced rate side by side so the comparison is based on your file, not a general rule. For the deeper math on when a penalty is worth paying to break free entirely, see is breaking your mortgage worth it.
Check today’s live rates at pekoe.ca/rates, updated daily. You can also get a pre-approval certificate in seconds.
Porting wins when your old rate is well below market and your new-money need is small, while breaking and refinancing wins when the penalty is minor or rates have moved in your favour.
When Porting Does Not Make Sense
Porting stops making sense once the blended rate lands close to what you would pay by refinancing outright, because at that point you gain nothing by preserving the old rate. It also fails to make sense if your lender’s product, service, or renewal terms are worse than what a competing lender is offering.
A large gap between your old balance and your new purchase price pulls the blend toward today’s rate anyway. If you need $400,000 of new money against a $100,000 ported balance, the blend will sit close to current market pricing regardless, so the “savings” from porting shrink to almost nothing while you are still locked into your existing lender’s rules.
Compare your actual blended number against a straight refinance before committing either way.
Frequently Asked Questions
Can I port my mortgage to a cheaper home and pocket the difference?
Generally no. Most lenders require the ported balance to be applied to the new property, and if your new home costs less than your existing balance, you may face a partial break penalty on the difference, since porting typically covers the full transfer, not a partial one. Confirm the exact treatment with your lender, as policies vary.
Does porting reset my mortgage term or amortization?
No, porting is meant to carry your existing rate and remaining term forward as-is. If you add new money for a bigger purchase, some lenders will let you extend or re-align the term on the blended portion, but that is a lender-specific option, not a default.
What happens if I cannot close on my new home before selling my old one?
A short gap between closings is common, and a bridge loan can cover the funds you need in between without breaking your port. See our guide to bridge financing for how that works and what it costs.
Is porting available on a variable-rate mortgage?
Some lenders allow porting on variable mortgages, but the privilege is far less consistent than on fixed mortgages, and terms differ significantly by lender. Check your specific mortgage commitment or ask your lender directly rather than assuming the same rules apply.
Do I need a new mortgage stress test to port?
Yes, in most cases. Porting keeps your rate, but requalifying for a new property still generally means passing the current stress test and debt-ratio requirements, so a change in your income or credit since your last approval can affect the outcome.
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Porting can protect a rate that no longer exists in the current market, but the decision only pays off if the numbers actually favour it over breaking and starting fresh.
Talk to a broker before you assume porting is your best move. We will run the port, the blend, and the break-and-refinance numbers side by side using your actual mortgage.
If your move happens to land close to your renewal date, the same negotiation skills apply to blends and payouts as they do to a straight renewal. Our Renewal Negotiation Playbook course walks through exactly how to negotiate those numbers directly with a lender.
Pekoe Mortgages is a licensed brokerage, FSRA Licence #13321 in Ontario and RECA licensed in Alberta.