Mortgage stress test
qualificationRate = max(contractRate + 2%, 5.25%)
The qualifying payment uses the higher stress-test rate rather than only the rate selected for the estimated monthly payment.
A full-stack calculator that estimates purchasing power, mortgage payments, debt-service ratios, default-insurance costs and Ontario closing costs against live Bank of Canada benchmark rates — with an itemized cash-to-close breakdown and no fabricated demo data.
Enter the financial details used to estimate purchasing power.
The interface keeps the experience simple, while the calculation engine separates payment math, qualification rules, insurance, taxes and closing costs into reusable modules.
The qualifying payment uses the higher stress-test rate rather than only the rate selected for the estimated monthly payment.
Housing costs include the qualifying mortgage payment, property tax, heating, applicable condo fees and ground rent.
This adds vehicle payments, student loans, revolving credit obligations and other recurring monthly debts.
The periodic rate is derived from the Canadian convention of nominal annual interest compounded semi-annually.
Mortgage-default insurance is calculated from the loan-to-value bracket and financed into the balance — but the 8% Ontario PST on that premium cannot be financed, so it's tracked separately as a cash-at-closing cost.
A binary search tests candidate purchase prices, and a 30-year amortization is only accepted for insured mortgages when the buyer is first-time or purchasing new construction — otherwise it's automatically capped at 25 years.
Many mortgage tools answer only one question: “What will my payment be?” This project combines qualification, affordability and closing-cost calculations in one guided journey, while explaining which financial factor is limiting the result.
Works backward from household income, property costs and debts to solve for a practical maximum home price, with every input starting at zero — nothing is pre-filled or assumed.
Calculates Gross Debt Service and Total Debt Service ratios and names the specific entered debt driving the result, instead of guessing at a generic cause.
Itemizes provincial and Toronto land-transfer tax, mortgage-default insurance, the 8% PST charged on that premium, and legal fees into a single visible cash-to-close breakdown.
Retrieves and normalizes real Bank of Canada rate data through a protected server-side endpoint, with a clearly labelled live/backup state and a source panel showing the raw series IDs.
Solve for maximum purchasing power, or test a specific price by editing it directly in the results panel and watching the qualification verdict update live.
The desktop split view becomes a guided single-column flow with a persistent estimate summary on tablet and mobile.
The calculator UI does not directly own the business rules. A server endpoint validates the input, retrieves normalized rate data and calls a pure calculation library. The same engine could later power other websites, advisor tools or partner applications.
Financial forms can feel intimidating. The interface uses a guided four-step structure, plain-language labels and live feedback so users can understand the estimate without being overwhelmed by every calculation at once.
Household, finances, property and mortgage assumptions are separated into manageable steps with visible progress.
A sticky desktop summary and persistent mobile estimate keep the customer connected to the outcome while editing inputs.
Horizontal ratio bars make GDS and TDS limits easier to compare and avoid decorative visualizations that can obscure the data.
Rate source, live-versus-backup status, the raw Bank of Canada series IDs and the qualification rate are all one click away, so the result feels explainable rather than arbitrary.
Every field starts at zero instead of a plausible-looking example. Nothing pre-fills income, debts or a purchase price, so a result only ever reflects what the customer actually entered.
30-year amortizations are only offered where the rule actually permits them, PST on mortgage-default insurance is itemized as its own cash cost, and "Prime Rate" is labelled for what it is — set by the banks, published by the Bank of Canada.
Open the working calculator to explore the guided form, an editable results panel, live Bank of Canada rate state and a fully itemized qualification and closing-cost breakdown.
This project is an educational portfolio demonstration. Results are estimates and do not represent mortgage approval, financial advice or a lender commitment.
Ontario mortgage demo