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.
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 TahmHami@gmail.com 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 we make money
HomeCalc is free and ad-free. Some users opt in to be contacted by a mortgage broker; we share those leads with brokers, which keeps the tools free. Calculator results are never influenced by this.
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