Home Equity & HELOC Calculator
How much of your home's equity can you actually borrow — under Canada's 80% total-lending rule and the 65% cap on a revolving line of credit — and what will it cost you each month, interest-only versus amortized?
How your home's value is split
Mortgage owed, equity you can access up to 80%, and the 20% cushion lenders keep locked.
Cost to borrow: interest-only vs amortized
Cumulative interest paid over 10 years on the amount you want to borrow.
Payment & interest by year
Amortized repayment of your desired amount — how much of each year goes to principal versus interest.
| Year | Payments | Principal | Interest | Balance |
|---|
How this is calculated
The 80% total-lending rule
Under OSFI's B-20 guideline, all lending secured against your home — first mortgage plus any HELOC or second mortgage — cannot exceed 80% of the property's appraised value. Your available equity is 0.80 × home value − mortgage balance. If your mortgage is already above 80% of value, this figure is $0 until you pay it down or the home appreciates.
The 65% HELOC cap
The revolving (re-borrowable) portion of a home equity line of credit is separately capped at 65% of value: 0.65 × home value − mortgage balance. You can still reach 80% combined, but the slice between 65% and 80% has to be a fixed, amortizing term — it can't revolve. A readvanceable mortgage combines the two: as you pay down the mortgage, the HELOC limit automatically readvances (grows) to keep you at your combined limit.
Cost of borrowing
Interest-only monthly cost is amount × rate ÷ 12 — you pay only the interest, so the balance never drops. An amortized payment uses P × r ÷ (1 − (1+r)^−n) with r the monthly rate and n = years × 12; it's higher but retires the debt. The chart compares cumulative interest over 10 years — interest-only rises in a straight line indefinitely, while amortized flattens as the balance falls.
HELOC pricing & risks
HELOCs are variable-rate, typically prime + 0.5% (prime is 4.45% as of July 2026, so ≈4.95%). Because it's secured by your home, a HELOC is callable — the lender can reduce or freeze your limit — and the rate moves with the Bank of Canada. Missing payments can lead to foreclosure. Interest-only minimums make it easy to carry a balance for years without paying anything down.
What this doesn't model
Appraisal costs, legal/discharge fees, prepayment penalties on refinancing your first mortgage, the mortgage stress test on your total housing costs, or income qualification (GDS/TDS). For a full refinance comparison see the refinancing calculator; for the underlying mortgage math, the mortgage calculator. Rules and rates verified as of July 2026.