Methodology

Every calculator calls the same TypeScript module in src/lib/calc/. The numbers it uses are JSON files in src/data/2026/. Each value has an effective date, a source URL, and a verification flag. Unit tests check the arithmetic and refuse to load a value that has no source.

Income tax and take-home pay

The paycheque calculator estimates a full year of employment income for a resident of the province you select. It applies 2026 federal and provincial brackets, the basic personal amount, the Canada employment amount, employee CPP or QPP, CPP2, and EI. Credits use the lowest bracket rate. Ontario adds surtax, the health premium, and the basic tax reduction. British Columbia adds its tax-year reduction. Quebec adds the federal abatement, QPIP, the reduced EI rate, and the deduction for workers.

It is not a full return. Spouse and dependant amounts, tuition, donations, benefits, and self-employed contributions are omitted. Payroll withholding can also differ in a year when a province changes a rate mid-year, because employers prorate the change. The calculator uses the tax-year rate and says when that differs from withholding.

Registered accounts

TFSA room illustrations add the CRA's annual dollar limits. RRSP new room is 18% of prior-year earned income, capped by the 2026 dollar limit, minus a pension adjustment you supply. FHSA room starts at $8,000, carries unused room up to $8,000, and stops at $40,000 of contributions. Growth projections compound an assumed effective annual return monthly. The rate is yours. It is not a forecast.

Sales tax and car loans

GST, HST and provincial sales tax use the CRA rate table in effect for 2026. Provincial tax is calculated on the pre-tax price. The car loan finances price minus trade-in, plus that tax, minus the down payment, then applies a standard monthly-compounded payment. Trade-in tax treatment varies. The page says so.

What we will not fill in

If a figure cannot be tied to a current official page, it is marked TODO-verify or left off the site. Manitoba's bracket thresholds are the current TODO-verify item: the CRA individuals page and the CRA payroll formulas do not match, and the calculator follows the payroll formulas while saying so.

Each calculator page repeats the parts of this note that apply to it, with the worked example for that tool.