Resilience Test

Your payment today is not your payment forever. Rates move, terms renew, and the payment you qualified for at 4.5% can look very different at 6.5%. This calculator shocks your actual mortgage payment by a rate increase you choose, then checks how many months your accessible savings would cover the new number.

One blunt question: if your rate jumped by the amount you set, could your savings carry the higher payment and your other debts for a meaningful stretch — or would you be counting weeks?

It does not model job loss, income drops, or a variable-rate payment hitting its trigger point. It does not predict rates. And it is not the formal regulatory stress test lenders use to qualify you (that uses a fixed contract-plus-2%-or-5.25% rule and full GDS/TDS ratios against property tax, heat and condo fees) — for that calculation, use the separate Stress Test calculator. This one tests your own budget against a rate shock you pick, using a simpler payment-only ratio and a savings-reserves verdict.

Your inputs, explained

Gross monthly household income. Before-tax income for everyone on the mortgage. It is only used to show a payment-only housing ratio, not a full GDS/TDS test — see "How the math works" below.

Mortgage balance. Your actual amount owing today, not the original loan amount or the home's price. The common error is entering what you originally borrowed instead of today's balance.

Current mortgage rate. The contract rate you are paying right now, not a rate you hope to get at renewal.

Amortization (years). Years left on the loan. A 25-year amortization five years in has 20 left, which changes the payment math. Find the remaining years on your mortgage statement.

Other monthly debt payments. Car loans, credit cards, lines of credit, student loans — anything else you pay every month besides the mortgage. The common error is omitting minimums on cards you "pay off monthly"; this calculator counts them as an ongoing obligation either way.

Accessible savings. Cash you could actually draw on — a chequing or savings account, a TFSA you would actually empty — not retirement accounts you would take a tax hit or penalty to touch.

Rate shock. A single slider, 0.5 to 6 percentage points, defaulting to 2. This is the size of the rate increase you want to test — not the formal regulatory stress test's fixed 2-point-or-5.25%-floor rule, just whatever shock you want to rehearse.

How the math works

The calculator re-amortizes your current mortgage balance at a higher rate — your current rate plus the rate shock you set — over the same remaining amortization. That gives a shocked payment, and subtracting your current payment from it gives the monthly dollar increase.

It also divides your current, unshocked payment by your gross monthly income to show a housing ratio. This is explicitly payment-only, not full GDS — a real GDS calculation would add property tax, heat and half of any condo fees before dividing, and lenders cap that fuller number at 39%. This calculator does not collect those extra costs, so treat the ratio it shows as a rough proxy, not a pass/fail test.

Finally, it adds the shocked payment to your other monthly debts to get your total obligation under the shock, then divides your accessible savings by that total to get months of reserves. That count sorts into a verdict: more than 6 months is "Solid", 3 to 6 is "Tight", and under 3 is "Fragile" — a labelled heuristic, not financial advice.

One more thing it computes: the rate shock that would push your reserves into the next worse verdict band, holding every other input fixed. Because a bigger shock always raises the shocked payment and always shortens how long your savings last, there is exactly one shock size where you cross from your current band into the next one down — the calculator solves for it directly instead of making you guess-and-check the slider.

Worked example

A household enters the calculator's own default numbers: gross income $12,500/month, mortgage balance $560,000, current rate 4.65%, 25-year amortization, $800/month in other debts, $40,000 in accessible savings, and the default 2-point rate shock.

Step 1: Payment at the 4.65% current rate, 25-year amortization. Monthly payment ≈ $3,146.

Step 2: Payment shocked to 6.65% (4.65% + 2%). Same balance, same amortization: ≈ $3,802 per month. The shock costs $656 more each month.

Step 3: Current housing ratio (payment-only). $3,146 ÷ $12,500 = 25.2%. Not full GDS — no property tax, heat or condo fees are in this number.

Step 4: Shocked obligation. $3,802 (shocked payment) + $800 (other debts) = $4,602 per month.

Step 5: Months of reserves. $40,000 ÷ $4,602 = 8.7 months. That is above 6 months, so the verdict is Solid.

Now the follow-on question: how much worse would the shock have to get before this household drops out of "Solid"? Solving for the rate shock where reserves fall to exactly 6 months finds 7.6 percentage points — a 12.25% rate in total, far past the 2-point default. At that shock, the payment would be about $5,877/month, the total monthly obligation about $6,677, and reserves would fall to roughly 6.0 months, flipping the verdict from Solid to Tight. That 7.6-point figure is not a prediction — it is a sensitivity check on how much room this household's $40,000 in savings actually buys before the verdict changes.

What this calculator doesn't cover

This tool starts from a mortgage balance you already have, so it has no home price, down payment, CMHC premium, or province-specific closing-cost math built in. For the cash-to-close side of a purchase — including provincial land transfer tax and CMHC insurance premiums and their sales tax — use the Land Transfer Tax and Mortgage Insurance calculators instead; this one is for stress-testing a mortgage you already hold or are about to take on.

Two edge cases worth knowing: the follow-on "shock that flips your verdict" figure searches up to 10 percentage points of shock, past the 6-point ceiling on the shock slider itself, because it is answering a hypothetical rather than validating a number you would actually type in. And if your reserves are already large enough that even a 10-point shock does not flip the verdict, the calculator says so honestly instead of forcing a number.

Questions to ask a professional

1. Ask your mortgage broker: how would my monthly payment actually change if my rate rose by the amount I tested here, and does the regulatory stress test I passed at purchase still reflect my situation today?
2. Ask your broker: if I renew in the next two years, will I face the formal stress test again, or am I exempt as a straight switch with my current lender?
3. Ask your lender: what is my trigger rate or payment cap if I am on a variable rate, and what happens when it is hit?
4. Ask a financial planner: is the number of months of reserves this calculator shows actually enough, given my job security, dependants and access to credit?