Methodology & Editorial Policy

Official Sources

usecos calculators are built from public, official sources wherever possible:

• Interest Act for Canadian mortgage interest-rate disclosure and semi-annual convention context.
• OSFI Guideline B-20 for mortgage stress-test context.
• CMHC mortgage loan insurance for insured-mortgage premium rules.
• Canada Revenue Agency for income-tax, payroll, CPP/EI, and GST/HST rates.
• US NHTSA, Transport Canada, and ISO VIN standards for vehicle decoding and recall guidance.

Calculation Assumptions

• Mortgage payments use Canadian semi-annual compounding converted to the selected payment frequency.
• Pay calculations are simplified annual estimates and are not a replacement for CRA PDOC or employer payroll withholding.
• GST/HST results use published provincial rates and do not determine product-specific exemptions.
• VIN decoding is local where possible; US NHTSA recall checks require sending the VIN to the recall API.

Known Exclusions

Tools may exclude lender-specific underwriting policies, personal tax credits and deductions, employer benefits, product-specific sales-tax exemptions, insurance quotes, appraisal costs, legal advice, or non-US recall campaigns. Pages call out major exclusions where they materially affect the result.

Update Schedule

Tax and payroll data is reviewed when official annual or mid-year tables are released. GST/HST and mortgage-source pages are reviewed when governments announce changes. High-traffic calculators are rechecked after source updates and before major content revisions.

Testing

Core calculation engines have automated tests for bracket thresholds, deductions, caps, and known regression cases. Before production deploys, usecos runs TypeScript checks, targeted calculation tests, and a production build.

Corrections

If you find an incorrect rate, formula, source link, or result, please contact us. Corrections that affect calculator outputs are prioritized, tested, dated, and deployed with a clear source update.