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Home Equity Line of Credit (HELOC) Calculator

Updated

A home equity line of credit (HELOC) is revolving credit secured by your home: you can borrow up to a limit, repay and borrow again, and you pay interest only on the amount you have drawn. This calculator estimates your maximum HELOC limit, how much of it is still available, and the monthly interest on what you have drawn. It is part of our refinancing and home equity guide. To compare a HELOC with other ways of borrowing against your home, see mortgage vs home equity loan vs HELOC and HELOC vs refinance.

How much you can borrow

At a federally regulated lender, two limits apply: the revolving part of a HELOC can't exceed 65% of the home's value, and everything borrowed against the home (the mortgage plus the HELOC, or a refinanced mortgage) can't exceed 80% of its value. HELOC room is therefore the lower of 80% of the value minus the mortgage and 65% of the value. Mortgage insurance can't take a refinance above 80%, except a refinance to build secondary suites that takes no equity out. The full limits are in the home equity guide.

The Financial Consumer Agency of Canada (FCAC) describes two kinds of HELOC:

  • Combined with a mortgage (also called a readvanceable mortgage): set up with the lender that holds your mortgage, and the available credit increases as you pay down the mortgage principal.
  • Standalone: separate from your mortgage, possibly with a different lender, and the available credit doesn’t grow as you pay the mortgage down.

FCAC’s equity example is a $500,000 home with $200,000 left on the mortgage: equity of $300,000, which is 60% of its value. Applying the limits above to that home:

  • 65% of value: $325,000
  • 80% of value minus the mortgage: $200,000
  • Maximum HELOC combined with the mortgage, the lower of the two: $200,000
  • Maximum standalone HELOC, 65% of value minus the mortgage: $125,000

The standalone figure treats the HELOC and the mortgage ahead of it as sharing the HELOC limit, which is what FCAC’s equity minimum for a standalone HELOC implies.

FCAC adds that the lender may value your home with an appraisal or by its purchase price, and that you can ask for a lower limit than you are approved for.

HELOC calculator

The rate box starts at the Bank of Canada’s chartered-bank prime rate, 4.45% as of 2026-09-30. Add the margin your lender quotes (FCAC’s example is prime plus 1%).

Home value
Mortgage balance
HELOC type
HELOC interest rate (prime 4.45% as of Sep 30, 2026, plus your lender's margin)
Amount drawn on the HELOC
Maximum HELOC limit
65% of home value (revolving limit)
80% of home value minus mortgage
65% of home value minus mortgage
Still available to draw
Monthly interest on the amount drawn (rate ÷ 12)
Equity after mortgage and HELOC
Equity as a share of value

What the calculator computes:

  • Combined with a mortgage: limit = the lower of the HELOC limit (a share of the home’s value) and the combined limit minus the mortgage, both from the rule above, never below $0.
  • Standalone: limit = the HELOC limit minus the mortgage, never below $0.
  • Still available = limit − amount drawn.
  • Monthly interest = amount drawn × annual rate ÷ 12, an approximation: FCAC notes that the lender charges interest as soon as you take money out, so your statement depends on when you drew.

What a HELOC costs

FCAC says most HELOCs have a variable rate, typically based on the lender’s prime rate; its example is prime plus 1% with a prime rate of 5.85%, for 6.85%. The lender can change the rate at any time, and a federally regulated lender must tell you in writing within 30 days. Current rates from specific lenders are on HELOC rates in Canada.

$100,000 drawn at prime plus 1%, using the prime rate above: 4.45% + 1% = 5.45%, assuming the rate doesn’t change.

  • Interest only: $100,000 × 5.45% ÷ 12 = $454.17 a month, and the balance stays at $100,000.
  • Repaid over 20 years (240 monthly payments, interest at the annual rate ÷ 12 each month): payment = $100,000 × i ÷ (1 − (1 + i)−240), with i = 5.45% ÷ 12, = $685.07 a month, or $64,416 of interest over the 20 years.
  • If the rate rose by 2 percentage points, the interest-only payment on the same $100,000 would rise by $100,000 × 2% ÷ 12 = $166.67 a month.

(Each percentage point of rate on $100,000 is $100,000 × 1% ÷ 12 = $83.33 a month, which is why the interest-only line multiplies the rate by 83.33.)

FCAC points out that if you only pay the interest, you won’t pay off the loan. Other costs it lists for setting up a HELOC are home appraisal fees, legal fees to register your home, title search fees, administration fees and monthly fees; cancelling can bring cancellation and discharge fees.

Uses and risks

FCAC lists managing unexpected expenses, consolidating debt and renovating your home as uses a HELOC may suit; see debt consolidation using home equity and renovation loans. The risks it lists:

  • if interest rates increase, you may have a hard time repaying, especially after large withdrawals;
  • if you don’t pay back what you owe, the lender may take possession of your home, and if you sell, the HELOC has to be repaid;
  • borrowing reduces your home equity, which can affect your financial stability and your options if you want to sell;
  • easy access to funds may tempt you to take on more debt than you can pay back.

Tax on HELOC interest

Interest is deductible when the borrowed money is used to earn income from a business or property, such as rent, interest or dividends, whatever secures the loan; it follows the money's current use, which you must be able to trace, and it isn't deductible on money used personally, on money borrowed for an RRSP, TFSA or FHSA contribution, or on an investment that can only produce capital gains. Borrowing against a readvanceable mortgage to invest relies on this rule.

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Sources

The figures and rules on this page come from these sources, last checked against them between September 25, 2026 and October 2, 2026. How we check facts.