Porting lets you take your mortgage with you when you sell one home and buy another. The Financial Consumer Agency of Canada (FCAC) describes it this way: if you sell your home to buy another one, a portable mortgage allows you to transfer your existing mortgage, including the balance, the interest rate and the terms and conditions (FCAC: Choosing a mortgage). This page covers how a port works, the timing that decides whether it succeeds, and the blended rate when the new home needs a bigger mortgage. It is part of our guide to renewing and managing your mortgage during the term.
How porting works
When you sell and buy, your existing mortgage can go one of three ways:
| Option | What happens |
|---|---|
| Port the mortgage | It moves to the new property with your rate and term, and no prepayment penalty is charged on the amount that moves |
| Break it and take a new mortgage | You pay the prepayment penalty and borrow again at the rates lenders offer now, from any lender |
| Let the buyer assume it | The buyer takes over your mortgage, if the lender approves them; see assumable mortgages |
A port stays with the same lender: to move to a different lender as part of the purchase, you would break the mortgage. Not every mortgage is portable. The FCAC suggests checking with your lender whether yours is eligible for porting and asking about any restrictions that may apply.
The size of the new mortgage changes the result:
- Same amount or close to it. The balance, rate and remaining term carry over to the new home.
- More money. The ported balance keeps its rate and the extra money is borrowed at a new rate; the two are blended (see below). The FCAC suggests asking your lender for details if you need to borrow more.
- Less money. If the new home costs less than the amount of your mortgage, the FCAC notes that you may pay a prepayment penalty, because part of the balance is being repaid early.
When porting is worth it
Porting is most valuable when your rate is below what lenders charge now (see current mortgage rates), because it keeps that rate and avoids a penalty. When your rate is above the rates on offer, a lower new rate may be worth more than the penalty you avoid by porting.
How large that penalty would be depends on your mortgage. On a fixed-rate mortgage the penalty is usually the higher of 3 months' interest on what you still owe and the interest rate differential (IRD). The lender usually uses the IRD when your mortgage rate is higher than its current rate and you signed your current contract less than 5 years ago. So when rates have risen since you signed, the interest rate differential is usually small or zero and the penalty falls back to the months’ interest, and when rates have fallen it can be large. Because the differential is charged on the interest left in your term, a fixed-rate penalty also tends to be largest early in the term, when the most months remain. On a closed variable-rate mortgage the penalty is typically 3 months' interest. How mortgage penalties are calculated works through both methods, and the mortgage penalty calculator gives an estimate.
To compare porting with breaking, set the penalty and fees against the interest you would save at the lower rate. The break-even calculation counts both the lower payments and the lower balance a lower rate leaves, and should I break my mortgage for a lower rate? covers the wider decision.
How to port your mortgage, step by step
1. Check your mortgage terms
Your mortgage commitment or contract says whether the mortgage is portable and on what conditions. The conditions that matter most:
- The portability window. Lenders set a period within which the sale of your old home and the purchase of the new one must both close for the mortgage to move. The length differs by lender and by product, so ask your lender for the window that applies to your mortgage, in writing.
- Whether a variable rate can be ported. Some lenders port variable-rate mortgages and some don’t; ask about your product.
- How extra money is priced. Ask what rate applies to new funds and how the lender blends it with your existing rate.
2. Tell your lender early and requalify
Contact your lender when you decide to sell, before you firm up a purchase. A port is usually treated as a new application for the new property: expect the lender to check your income and credit again and to have the new home appraised. If your income has fallen or your debts have risen since you first qualified, the port can be refused even for the same amount. If you add money, the lender may also apply the mortgage stress test to the new mortgage.
3. Line up the closing dates
Both closings must fall inside the portability window. The most common reason a port fails is a timing gap.
Suppose your contract gives you 90 days from the sale closing to close on the new home. Your sale closes November 1 and your purchase closes February 1. That is 92 days (30 in November, 31 in December and 31 in January), two days past the window, so the port is refused and the prepayment penalty applies.
Ways to close a gap:
- Move one closing date while the deals are still being negotiated, so both fall inside the window.
- Ask for an extension. Some lenders will consider extending the window if you ask in writing with a firm purchase agreement; ask yours before you rely on it.
- Use bridge financing to cover the down payment when you buy before your sale closes. It doesn’t extend the portability window; the bridge financing calculator estimates its cost, and bridge financing explained covers how it works.
4. Complete the port
The lender issues a new commitment for the ported mortgage, and a real estate lawyer or notary discharges the mortgage from the old property and registers it on the new one. Budget for legal fees, the appraisal and any administration fee the lender charges, and for title insurance if you buy it.
The blended rate when you borrow more
When the new home needs a larger mortgage, the ported balance keeps its rate and the new money is lent at a new rate. A simple way to see the result is the average of the two rates, weighted by amount:
Blended rate = (ported amount × ported rate + new amount × new rate) ÷ total amount
You port $350,000 at 2.89% and add $150,000 at 4.84%.
- Ported part: $350,000 × 2.89% = $10,115 of interest a year
- New part: $150,000 × 4.84% = $7,260
- Total: $17,375 on $500,000
- Blended rate: $17,375 ÷ $500,000 = 3.475%
The blended rate sits between your old rate and the new one, closer to whichever amount is larger. Lenders differ in how they blend: some weight the rates by the time left in each term as well as by amount, and many put the whole blended mortgage on a new term, so the rate you are quoted is the figure to compare. The blended mortgage guide covers the methods, including blending to a new term.
Questions to ask your lender
- Is my mortgage portable, including if it has a variable rate?
- How long is the portability window, and does it run from the sale closing or the purchase closing?
- What rate applies to new money, and how is it blended with my current rate?
- Will the blended mortgage keep my remaining term or start a new one?
- Do I have to requalify, and will the new property be appraised?
- What happens if the new mortgage is smaller than my current balance?
- What fees apply to the port?
Common porting mistakes
| Mistake | What can happen |
|---|---|
| Assuming the mortgage is portable | You find out after listing that it isn’t, or that your product has restrictions |
| Missing the portability window | The port is refused and the prepayment penalty applies |
| Assuming you’ll requalify | Lower income or higher debts can stop the port |
| Buying a less expensive home | Repaying part of the balance can bring a prepayment penalty |
| Changing property type | Moving from a home you live in to a rental, or to a property the lender treats differently, can change what it will lend |
| Not comparing a port with a break | When rates have fallen, keeping your old rate may cost more than the penalty |
Porting checklist
Before you list your home
- Confirm that the mortgage is portable and get the window in writing
- Ask how new money would be priced if you buy up
- Get a penalty quote, to compare porting with breaking
While you sell and buy
- Set both closing dates inside the window
- Apply for the port before the purchase is firm
- Arrange bridge financing if you buy before the sale closes
- Book a lawyer or notary for both transactions
At closing
- Sign the new mortgage documents
- Confirm that the old mortgage is discharged and the ported one registered
- Check the payment amount and schedule on the new mortgage
Related pages
- Moving to another province with a mortgage
- Mortgage renewal guide
- Blend and extend, the mid-term option when you stay in the same home
- Big bank vs monoline lenders
- Mortgage calculator
Sources
The figures and rules on this page come from these sources, last checked against them on September 29, 2026. How we check facts.
- Financial Consumer Agency of Canada: Breaking your mortgage contract
- Financial Consumer Agency of Canada: Mortgage fees: Prepayment penalties
- RBC: Variable Rate Mortgage | RBC Royal Bank of Canada