Quick answer
What this means in practice
A portable mortgage may let you carry some existing terms to a new property instead of paying out the entire mortgage. The feature is conditional: the lender still reviews the borrower, property, amount, dates, and contract rules.
Key takeaways
- Porting is a contract feature that may let a borrower move an existing mortgage, or part of it, to a new property.
- Porting may be worth testing when breaking the existing mortgage would create a material penalty or when the existing rate and features remain competitive.
- Contact the current lender before fixing the sale and purchase dates.
- If the new mortgage is larger, a lender may combine the ported balance with additional borrowing at a current rate.
Compare the lender's written port offer with the dated break penalty and a complete new-mortgage option. The answer depends on actual dollars, timing, and flexibility—not a generic savings claim.
What is mortgage porting?
Porting is a contract feature that may let a borrower move an existing mortgage, or part of it, to a new property. It does not transfer automatically. The lender must approve the borrower, new property, transaction, timing, and any additional funds under its current rules.
Read the port clause for deadlines, eligible property types, minimum amounts, and what happens to the original term and penalty.
When porting makes sense
Porting may be worth testing when breaking the existing mortgage would create a material penalty or when the existing rate and features remain competitive. It can also reduce value if the new structure extends the term, blends at an unfavourable rate, or prevents a better full-mortgage option.
Compare written port and break scenarios on the same balance and time horizon.
How porting works
Contact the current lender before fixing the sale and purchase dates. Ask for its port rules, qualification documents, property requirements, deadlines, and treatment of any gap between closings. The lender reviews the new application and issues conditions if the port is approved.
The lawyer then coordinates the payout and new registration. A penalty may be charged and later refunded under some port programs, so confirm the cash-flow timing in writing.
Blend and extend explained
If the new mortgage is larger, a lender may combine the ported balance with additional borrowing at a current rate. The resulting blended rate, term, and prepayment conditions are calculated under that lender's product rules. Some ports preserve the remaining term; some offers extend it.
Ask for the calculation, not just the blended headline rate, and compare the interest and penalty implications over the full new term.
Porting vs breaking: cost comparison
Compare the current lender's dated payout and port offer with a new mortgage offer. Include the penalty and possible refund, legal and appraisal costs, blended rate, new term, interest over the chosen horizon, and the value of lost or gained features.
Use actual written figures. Generic savings examples can be misleading because the balance, penalty formula, port rules, and closing dates control the result.
When porting is not ideal
Porting may fail or underperform when the new property is outside the lender's appetite, the borrower no longer qualifies, the required amount exceeds the port program, the dates fall outside the permitted window, or a new lender provides a better total-cost option after the penalty.
Keep a backup financing path until the lender has approved both the borrower and property.
Timing considerations
Port windows and closing-gap rules vary by lender and contract. Confirm the earliest and latest eligible dates, whether simultaneous closings are required, how a gap is handled, and when any charged penalty is refunded.
Coordinate the lender, broker, and real-estate lawyer before firming dates. Missing a contractual deadline can turn a planned port into a full payout and penalty.
