A lower advertised rate isn't a reason to break your mortgage. It's a reason to get out a calculator. The question is whether the savings you can actually keep, over the time you expect to keep the new mortgage, exceed what it costs to leave the old one.
That sounds obvious until a quoted penalty arrives. On a fixed mortgage, it can be much larger than three months' interest. And even if the monthly payment falls, that doesn't automatically mean you've saved money. You may simply have stretched the debt over more years. Here's a way to make the decision without leaning on a sales pitch.
Start with the exact payout number
Ask your current lender for a written payout statement for a specific date. It should show your outstanding principal, the prepayment charge, any discharge or administration fee, and how long the quote is valid. If you have a cash-back mortgage, ask whether unearned cash back must be repaid. Don't substitute an online penalty estimator for this number: it can be a useful first pass, but the lender's contract and calculation determine the bill.
Also ask what happens if you use an available lump-sum prepayment privilege before closing. Some contracts let you reduce the balance used to calculate the charge; others have timing rules or restrictions. Don't send money based on an assumption. Have the lender confirm how it will treat the prepayment first.
Three months' interest isn't always the whole story
For many closed variable-rate mortgages, the charge for breaking the term is roughly three months' interest on the balance at the contract rate. As a simple illustration, $400,000 × 6% × 3 ÷ 12 equals about $6,000. That's only a rough estimate; the contract may use a different daily-interest method or include other charges. An open mortgage may have different prepayment rules altogether.
A closed fixed-rate mortgage commonly charges the greater of three months' interest and the interest rate differential, or IRD. Broadly, IRD measures the interest the lender says it loses when you leave your fixed term early, comparing your contract rate with a rate for a term similar to the time you have left. But the comparison rate isn't universal. Some lenders account for the original discount off a posted rate; some use different reference rates and rounding rules. Two people with the same balance, rate and remaining term can receive very different quotes from different lenders.
For example, imagine 24 months remain on a $400,000 fixed loan at 5%. Three months' interest is about $5,000. A plain illustration with a 1-percentage-point rate gap over two years suggests $8,000 of differential interest before any lender-specific adjustments. The actual IRD could be different. Don't treat that $8,000 as a payout quote; use it to see why 'my penalty is probably three months' interest' can be an expensive guess.
Do the comparison over a real holding period
First, total every cost of changing mortgages: the written penalty, appraisal if required, legal and registration work, discharge fees, and any new lender fees. If a lender covers a cost, check whether the offer carries a higher rate or conditions elsewhere. If you add the costs to the new mortgage, they're still costs, and you'll pay interest on them.
Next, compare the two paths for the same period, ideally until the current term would have ended. Keep the mortgage balance and amortization assumptions consistent. Look at interest paid and the remaining principal at the end, not just the monthly payment. A lower payment created by resetting a 17-year remaining amortization to 25 years may improve cash flow, but it isn't the same as lowering the cost of borrowing.
For a quick screening test, divide all switching costs by a credible monthly saving. Suppose the penalty is $4,500 and other costs are $1,500, while like-for-like savings are $300 a month. The simple break-even point is 20 months. If you have only 12 months until renewal, that's a warning sign. It isn't a full comparison: the interest balance changes month by month and your replacement rate may change at its next renewal. But it's an excellent way to rule out a weak deal early.
When leaving early can make sense
One case is a modest penalty, substantial rate improvement, and enough time left in the old term to recover the costs. That combination is more plausible when the penalty is three months' interest, though a fixed mortgage can work too if the lender's IRD is low. What matters is the written charge and the new offer, not the mortgage label alone.
Another case is expensive debt. If you're carrying credit-card balances at much higher rates, consolidating them into a mortgage may reduce interest and monthly pressure. But moving unsecured debt onto your home introduces risk, and a much longer repayment period can erase the apparent saving. Compare a specific repayment plan for that consolidated amount, including the penalty and fees. The same caution applies when accessing equity for a needed expense: the benefit may be real, but don't call it a rate saving if you're borrowing more.
A move, a change in household finances, or the need to restructure ownership can make a refinance useful even when the pure rate calculation is close. In those cases, separate the financial need from the rate claim. That makes it easier to compare alternatives on their own merits.
When waiting is probably better
If renewal is near, waiting can avoid the break charge altogether. If the IRD is large, a tempting new rate may not recover it before the old term ends. And if you expect to sell soon, don't calculate savings over five years when you only expect to own the home for one. Ask whether a portability option applies, but confirm its conditions rather than assuming you can take the mortgage with you.
Sometimes you need funds but don't need to replace a favourable first mortgage. A home equity line of credit or second mortgage may let you keep that rate, although those options bring their own interest costs, fees and qualification rules. They aren't automatic winners; put their total costs beside the refinance. Our options comparison and break-even estimator can help frame the questions, but the lender's payout statement is the number to start with.
A useful next step
Get the written payout quote, the current balance and remaining amortization, then compare real offers on the same timeline. If you want a second set of eyes, Meshesha Robel, Mortgage Agent Level 2 with Mortgage Alliance, can walk through the penalty and your alternatives. Call or text (647) 342-1355, or email mrobel@mesheshagroup.com. If staying put looks better, that's a useful answer too.
Examples are illustrative only. Rates, qualification and penalty amounts depend on your lender and mortgage agreement. Confirm your exact payout with your current lender.