HELOC available equity + monthly cost.
Available HELOC credit
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Monthly interest-only payment on draw
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How much equity a Canadian HELOC unlocks
A home equity line of credit lets you borrow against the value you have built in your home, drawing and repaying like a giant credit card secured by the property. Canadian rules cap a standalone HELOC at 65 percent of the home's value, and your existing mortgage eats into that ceiling. So the available credit is 65 percent of the home value minus whatever you still owe on the mortgage. This calculator runs that subtraction, then tells you the interest-only monthly cost on whatever portion you actually draw. There is a related limit worth knowing: a HELOC combined with your mortgage as one bundled product can go up to 80 percent of the home's value, but the revolving HELOC portion within that bundle is still held to the 65 percent line. The rest above 65 percent has to be a regular amortizing mortgage segment that you pay down on a schedule.
Interest-only, and why that cuts both ways
The minimum payment on a HELOC is interest only. There is no forced principal repayment and no fixed amortization schedule, which is what makes it flexible and also what makes it dangerous. The rate floats, usually at the lender's prime rate plus a margin of around half a percent, so your payment moves whenever the Bank of Canada shifts rates. Pay only the interest and the balance never falls. That is fine for a short-term need you plan to clear, but a trap if the draw quietly becomes permanent debt.
An $800,000 home with a $400,000 mortgage
Say your home is worth $800,000 and you owe $400,000. The 65 percent ceiling is $520,000. Subtract the mortgage and $120,000 of HELOC room remains. Draw $50,000 of it at a 6.5 percent rate, and the interest-only payment is that balance times the monthly rate.
| Step | Value |
|---|---|
| Home value | $800,000 |
| 65% lending ceiling | $520,000 |
| Less mortgage balance | $400,000 |
| Available HELOC credit | $120,000 |
| Amount drawn at 6.5% | $50,000 |
| Monthly interest-only payment | $271 |
The chart maps the home's value into three slices: the mortgage you already owe, the HELOC room that opens up, and the equity cushion the 65 percent rule keeps off-limits to lenders.
Smart uses and the readvanceable trap
A HELOC shines for renovations that add value, as a low-cost emergency reserve, or in the Smith Manoeuvre, where you borrow to invest and the interest can become tax-deductible because it is incurred to earn income. The judgement call is discipline. Because the balance can sit indefinitely on interest-only payments, it is easy to treat a HELOC as free spending money and watch the draw creep upward. A practical rule: give every draw a repayment date and a purpose before you tap it. And remember a readvanceable HELOC, the kind that grows as you pay down your mortgage, ties your borrowing power to one lender and can make switching mortgages at renewal more cumbersome.
Frequently asked questions
Is HELOC interest tax-deductible in Canada?
Only when the borrowed money is used to earn income, such as buying dividend-paying stocks, an investment property, or funding a business. Interest on a HELOC drawn for a renovation, a car, or a vacation is personal and not deductible. The Canada Revenue Agency looks at the use of the funds, not the type of loan, so keeping investment borrowing in a separate HELOC sub-account makes the deduction far easier to defend.
Can the lender reduce or cancel my HELOC limit?
Yes. Unlike a fixed mortgage, a HELOC is demand credit, and the lender can lower your limit or freeze further draws, typically if your home value drops sharply or your credit deteriorates. This is why a HELOC is a weaker emergency plan than it looks. The room you are counting on can shrink in exactly the downturn when you most want to use it.