Last reviewed: July 13, 2026
How does HomeCalc keep calculators accurate?
HomeCalc is built by a product engineer, not a licensed advisor. Every formula here comes directly from official Canadian sources — CMHC, OSFI, the CRA, the Bank of Canada, and provincial finance ministries — and is unit-tested against those documents. We show you the source and the date we last verified it, so you can check the number yourself. This is a calculator, not personal financial advice: confirm anything that matters with a mortgage broker, CPA, or real-estate lawyer.
Our standards in one paragraph
HomeCalc is built by a product engineer, not a licensed advisor. Every formula here comes directly from official Canadian sources — CMHC, OSFI, the CRA, the Bank of Canada, and provincial finance ministries — and is unit-tested against those documents. We show you the source and the date we last verified it, so you can check the number yourself. This is a calculator, not personal financial advice: confirm anything that matters with a mortgage broker, CPA, or real-estate lawyer.
Where our numbers come from
Every calculator family traces to a primary Canadian publication. When a rule changes, we update the calculator and bump the “Last verified” date on the tool page.
| Calculator family | Official source | Where to check |
|---|---|---|
| Mortgage payment / affordability / stress test | OSFI B-20 (stress test) + CMHC insurance rules (Dec 2024) | osfi-bsif.gc.ca · cmhc-schl.gc.ca |
| Down payment / CMHC insurance | CMHC (Dec 2024 rules) | cmhc-schl.gc.ca |
| Land transfer tax | Provincial finance ministries + City of Toronto (MLTT) | fin.gov.on.ca · gov.bc.ca · toronto.ca · gov.mb.ca |
| Income tax / salary after tax | CRA tax rates + CRA payroll formulas (T4127) | canada.ca (CRA) |
| Capital gains / CCA / flipping tax | CRA | canada.ca (CRA) |
| Rent increase | Provincial guideline (Ontario) | ontario.ca |
| Rates context | Bank of Canada | bankofcanada.ca |
- Mortgage / stress test / insurance: OSFI B-20 and CMHC (Dec 2024 insurance rules).
- Land transfer tax: Ontario Ministry of Finance, City of Toronto (MLTT), Government of B.C., Government of Manitoba.
- Tax & payroll: CRA rates and T4127 payroll formulas.
- Rates context: Bank of Canada.
How we test the formulas
Formulas are implemented in TypeScript and unit-tested against the official documents above. Those tests run on every build. If a calculator output ever disagrees with the source document, the source wins — we fix the code.
When we update
We treat these as triggers to re-verify and, when needed, ship an update:
- Bank of Canada rate announcements
- CRA annual indexation of tax brackets and payroll formulas
- CMHC or OSFI rule changes
- Provincial budget or land-transfer / rent-guideline changes
Each calculator shows its own “Last verified” date in the Accuracy box. Methodology for the site as a whole is reviewed whenever those upstream sources change.
Where we go beyond applying published rules and analyse the underlying data ourselves, the workings are published in full — see HomeCalc research and reports, where each study states its data sources, method, and coverage period and ships a downloadable dataset. The same calculation engines are also queryable directly by AI assistants through our free MCP connector.
What HomeCalc is not
HomeCalc is not personal financial, tax, or legal advice. It is not a licensed mortgage brokerage, accounting firm, or law practice. Confirm anything that matters for your situation with a mortgage broker, CPA, or real-estate lawyer before you act.
Who builds this
Hami Tahm, founder — a product engineer and first-time buyer in Toronto. Explicitly not a licensed advisor. The work here is careful sourcing and careful math, not licensed advice.
Corrections
If you spot an error, email Hami@HomeCalc.ca with “Correction” in the subject line. Include the URL, what looks wrong, and the official source. We fix it and publish a dated correction note on the affected page.
How HomeCalc stays free
HomeCalc is free, ad-free, and your calculations are never sold or shared. If you choose to be connected with a licensed mortgage broker, we ask your consent first and only pass on what you agree to. That optional service is how we plan to keep the tools free.
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