Mortgage Porting in Canada: What It Is and When It Makes Sense

Porting a mortgage means transferring your existing mortgage — including its interest rate, balance, and remaining term — from a property you're selling to a new property you're buying. It's a way to avoid the prepayment penalty you'd face by breaking your mortgage early.

Not all mortgages are portable. And even when yours is, the question of whether to port depends on a specific set of circumstances. Here's what you need to know.

How mortgage porting works

When you sell your home and buy a new one, you'd normally need to break your existing mortgage, triggering a penalty (3 months' interest on variable, or IRD on fixed). Porting avoids that penalty by carrying the mortgage across to the new property.

The mechanics:

1. You apply to port your existing mortgage to the new property.
2. Your lender must approve the new property as suitable collateral.
3. You must still qualify under current underwriting rules (income, GDS/TDS ratios, stress test).
4. The closing dates of the sale and purchase must typically align within 30–90 days (the exact window varies by lender).

Porting when you need more money: blend and extend

What if the new home costs more than the old one? You need to borrow more than your existing balance. In this case, lenders typically offer a blend-and-extend:

• Your existing mortgage balance continues at your original rate for the remaining term.
• The additional funds needed are offered at today's rate for a new term.
• The lender blends these two rates into a single "blended" payment, and extends the term to match the new loan's term.

Example: You have $350,000 remaining at 3.20% with 2 years left. Your new home requires $500,000, so you need an additional $150,000. The lender offers 5.00% on the top-up. Your blended rate on the full $500,000 is approximately 3.74%, with a new 5-year term.

Whether that blended rate is better than simply paying the penalty and taking a fresh mortgage at today's best rate is a calculation worth doing every time.

Porting when you need less money: porting down

If the new property is less expensive and you're paying down the mortgage to port, some lenders charge a partial penalty on the reduced portion. Others allow it without penalty. Check your mortgage contract carefully — this is often overlooked.

When porting makes sense

• Your current rate is significantly below today's rates and you have a substantial remaining term (e.g., 3+ years at a rate 1.5–2% below current market).
• The penalty to break your mortgage would be large — particularly a fixed-rate IRD penalty when rates have fallen.
• Your closing dates can be reasonably aligned.

When porting may not make sense

• Your existing rate is close to or above current market rates — there's no rate advantage to preserve.
• You're near the end of your term anyway (less than 6 months remaining makes the penalty small and porting complex).
• The blend-and-extend calculation results in a blended rate higher than a fresh mortgage would offer — this sometimes happens when the top-up is large relative to the ported balance.
• Your new property is in a different province or is a type of property your lender won't accept as collateral.

Always do the math before you decide

The penalty-vs-port calculation is specific to your numbers. Get both figures from your lender — the exact penalty amount, and the terms of the port — then compare them against the best fresh mortgage you could get today. Use our refinance calculator to model the breakeven point.