Blog > Porting vs. Breaking Your Mortgage When Moving Up in Markham
Should I port or break my mortgage when moving up to a bigger home in Markham
If you have a fixed-rate mortgage, breaking it early usually costs the higher of three months’ interest or the interest rate differential (IRD). At many big banks, the IRD uses posted rates and can reach tens of thousands of dollars. Porting moves your existing mortgage to the new home and usually avoids the penalty. If you need to borrow more, many lenders blend your current rate with today’s rate on the new money. Breaking can still make sense if a new rate saves more than the penalty over the term, or if porting does not fit your timing. Ask your lender for the exact penalty in writing before you sign anything.
Why This Decision Matters for Move-Up Buyers
Moving from a townhouse or semi to a larger detached home in Markham often happens in the middle of a five-year term. The mortgage on the current home has to be dealt with, and the choice can change your moving budget by thousands of dollars.
Michael John Lau, a REALTOR® with the Kaizen Real Estate Team, one of the most active real estate teams in Markham and York Region, encourages move-up families to call their lender before listing, because the mortgage terms can affect the best closing dates for both the sale and the purchase.
How Prepayment Penalties Are Calculated
According to the Financial Consumer Agency of Canada, the penalty on a fixed-rate mortgage is usually the higher of:
- Three months’ interest on the balance, or
- The interest rate differential (IRD): the difference between your rate and a current comparison rate, applied to the balance for the time left on your term.
The comparison rate is where lenders differ. Many large banks use a posted-rate method: they take today’s posted rate for the remaining term and subtract the discount you received when you signed. If you received a large discount, the IRD can be much higher than you expect. Variable-rate penalties are often three months’ interest, but check your contract.
A Worked Example
This is an illustration only. Your lender’s method and figures will be different.
| Example | |
|---|---|
| Mortgage balance | $600,000 |
| Your rate (posted 6.50% minus a 1.50% discount) | 5.00% |
| Time left on the term | 30 months |
| Today’s posted rate for a similar term, minus your 1.50% discount | 3.50% |
| Three months’ interest | $7,500 |
| IRD: 1.50% difference x $600,000 x 2.5 years | $22,500 |
| Penalty (the higher amount) | $22,500 |
Lenders usually calculate the IRD on a more detailed basis, so actual amounts vary. The point is the scale: a large discount combined with falling rates can turn a penalty you expected to be under $10,000 into one above $20,000.
Moving up in Markham? Call Michael John Lau, REALTOR®, at (416) 700-0286 to plan closing dates that work with your mortgage.
How Porting Works
Porting means taking your existing rate, balance and remaining term to your new home. The Financial Consumer Agency of Canada notes that it saves you from breaking your contract and starting a new one.
- You must qualify again for the new property, including income, credit and the new home’s appraisal.
- Timing rules apply: many lenders require the sale and purchase to close within a set window, so ask for yours in writing.
- Need more money? Lenders often blend your existing rate with a current rate on the additional amount, sometimes called blend and increase.
- Need less? Paying down part of the balance may trigger a partial penalty.
Blending Rates
A blended rate combines your existing rate on the current balance with today’s rate on new borrowing, weighted by the amounts. Some lenders also offer a blend and extend, which resets the term on a blended basis. If your current rate is higher than today’s rates, blending can lower your overall rate and avoid a penalty. If your current rate is lower, blending protects part of your low rate on the existing balance.
Ask the lender to show the blended rate, the new payment and the term in writing, and compare it with a new mortgage elsewhere.
Managing the Gap Between Closing Dates
| Situation | What to plan for |
|---|---|
| Purchase closes before the sale | Bridge financing to cover the down payment until the sale funds arrive |
| Sale closes before the purchase | Temporary housing, storage, and the lender’s porting window |
| Same-day closing | Least carrying cost, but very little room if something is delayed |
For a full timeline, see whether to buy or sell first in Markham.
When Paying the Penalty Can Make Sense
Breaking can be the better choice when a new mortgage saves more interest over the remaining term than the penalty costs, when porting would not cover the amount you need, or when your lender’s porting window does not fit your dates. A quick comparison:
- Get the exact penalty from your lender in writing.
- Estimate the interest you would save at a new rate over the same months left on your term.
- Add any legal, appraisal and discharge fees.
- Compare the total with the cost of porting and blending.
Before breaking, use any annual prepayment privileges first, because they can reduce the balance the penalty is based on. Ultimately, the decision is yours. The goal is to make sure you have all the information.
Next Steps
- Buy first or sell first?: a plan for move-up families.
- Mortgage calculator: compare payments on a new mortgage.
- Request a free home evaluation: know what your current home could sell for.
Frequently Asked Questions
What is the penalty for breaking a fixed mortgage in Canada?
It is usually the higher of three months’ interest or the interest rate differential (IRD), according to the Financial Consumer Agency of Canada. Lenders calculate the IRD in different ways.
Why are big bank mortgage penalties so high?
Many big banks calculate the IRD using posted rates minus your original discount. A large discount and lower current rates can make the penalty much higher.
What does porting a mortgage mean?
Porting moves your existing mortgage rate, balance and term to a new home, which usually avoids a prepayment penalty. You must qualify again and meet the lender’s timing rules.
What is a blended mortgage rate?
A blended rate combines your current rate on the existing balance with a current rate on any new borrowing, weighted by the amounts.
Is it ever worth paying a mortgage penalty?
Yes, if a new mortgage saves more interest over the remaining term than the penalty and fees, or if porting does not fit your timeline or borrowing needs.
How can I reduce my mortgage penalty?
Use your annual prepayment privileges before breaking the mortgage, ask about porting, and get the exact penalty in writing before making a decision.
Work With Michael John Lau in Markham
Michael John Lau helps Markham move-up families plan the sale and purchase together, including closing dates that work with their mortgage. He works alongside your mortgage professional, so the decision to port or break is made with real numbers. The goal is a smooth move without costly surprises.
📞 Contact Michael John Lau, REALTOR®
🌐 www.callmikelau.com
Planning your move up in Markham?
Michael John Lau can coordinate your sale and purchase timeline around your mortgage options.
Michael John Lau, REALTOR® · Markham, Ontario · (416) 700-0286
Disclaimer. Michael John Lau is a licensed REALTOR® serving buyers and sellers in Markham, Ontario and the Greater Toronto Area. Penalty methods are described by the Financial Consumer Agency of Canada, as available on October 7, 2026. The Bank of Canada policy rate was 2.25% as of its September 2, 2026 decision. The example is simplified for illustration; lenders calculate penalties differently. Michael John Lau is not a lawyer, accountant, tax advisor or mortgage professional. This article is general information, not legal, tax or financial advice. Speak with a qualified professional about your own situation.