How Mortgage Porting Works When You Move

Moving to a new home doesn't always mean starting your mortgage from scratch. For buyers in the middle of a fixed term, porting allows you to carry your existing mortgage, rate, and terms over to the new property. It can be a useful way to avoid prepayment penalties, but the process comes with conditions that are worth understanding before you assume it will go smoothly.

What Porting Actually Means

Porting a mortgage means transferring your current mortgage, including its remaining term, interest rate, and balance, to a new property when you sell one home and buy another. It is most relevant for homeowners with a fixed-rate mortgage who are partway through their term, since breaking that term early typically triggers a prepayment penalty.

Instead of discharging the old mortgage and penalizing yourself for leaving early, porting lets you keep the same rate and conditions attached to the new address. This can be particularly appealing if you locked in a lower rate than what is currently available, since you may be able to hold onto that rate rather than requalifying at today's terms.

Conditions That Usually Apply

Porting is not automatic just because your lender offers the feature. You generally need to qualify for the mortgage again under your lender's current underwriting rules, which may include passing the mortgage stress test even though you already own a home. Lenders will typically reassess your income, credit, and debt levels at the time of the port, not just rely on your original approval.

Timing also matters. Most lenders require the sale of your existing home and the purchase of the new one to close on the same day, or within a short window set by the lender, often a matter of days. If the timelines do not line up, which can happen in a competitive housing market, you may lose the ability to port and end up paying the penalty anyway.

The new property also needs to meet the lender's criteria. A move from a detached house to a condo, or into a different price range or location, could affect how the lender views the deal, even if the mortgage itself is being carried over.

When You Need to Borrow More

Many people moving up the property ladder need a larger mortgage for their next home. In these cases, lenders often use a blend-and-extend approach, where your existing rate is blended with current rates on the additional amount you are borrowing. The result is usually a new blended rate that sits somewhere between your old rate and today's rate.

For example, if your original mortgage had a rate of 4 percent with a balance of 300,000 dollars, and you needed to borrow an additional 150,000 dollars at a hypothetical current rate of 5.5 percent, the lender might calculate a weighted blended rate based on those two amounts. This is illustrative only, as actual blended rate formulas vary by lender, but it shows how the new rate reflects both the old and new portions of your mortgage.

This approach can still work out favourably compared to breaking your mortgage entirely and starting fresh, though it is worth asking your lender exactly how they calculate the blend so you understand the full cost.

Situations Where Porting Might Not Make Sense

Porting is not always the better option. If current rates have dropped significantly since you signed your mortgage, you might come out ahead by breaking your term, paying the penalty, and starting a new mortgage at a lower rate, depending on how the numbers work out in your specific situation.

Porting can also become complicated if you are changing lenders at the same time, since the feature is generally tied to staying with your existing lender. If you are considering a switch for better terms or service, that usually means forgoing the ability to port and dealing with your mortgage as a fresh application instead.

Because the math involves comparing prepayment penalties, blended rates, and qualification requirements all at once, this is an area where speaking with a mortgage broker or professional can help you see the full picture before deciding which path fits your move.

Key Takeaways

• Porting lets you transfer your existing rate and term to a new property, which can help you avoid prepayment penalties
• You typically need to requalify under current lending rules, including the mortgage stress test, even if you already hold the mortgage
• Closing dates for your sale and purchase usually need to align closely, or the port may not be possible
• Borrowing additional funds often results in a blended rate rather than keeping your original rate on the full amount
• Comparing porting against breaking your mortgage outright is worth doing with a mortgage professional before you commit

Disclaimer: This article is for informational purposes only and does not constitute financial, legal, or mortgage advice. Any numbers, rates, or scenarios mentioned are examples only and may not reflect current market conditions. Always consult a licensed mortgage professional or financial advisor for guidance specific to your situation.