How we calculate

Methodology

Last updated 1 October 2026

Our approach

Each calculator applies the published rules of one tax authority for one tax year. All rates, thresholds and limits live in per-country, per-year data files, each value annotated with its official source. The calculation runs entirely in your browser.

Results are estimates for typical salaried employees. We model the parts of the tax system that affect most people and say plainly what we leave out, below.

India

Default year: FY 2026-27 (Tax Year 2026-27), under the Income-tax Act, 2025. FY 2025-26 remains selectable for belated and revised returns. Section numbers are shown in the new Act's numbering with the 1961 Act number in brackets, e.g. Section 156 (earlier 87A).

Included: new and old regime slab rates; ₹75,000 (new) and ₹50,000 (old) standard deduction; the Section 156 rebate (₹60,000 up to ₹12 lakh, with marginal relief, in the new regime; ₹12,500 up to ₹5 lakh in the old); 4% health and education cess; old-regime deductions you enter, capped at ₹1.5 lakh for Section 123 (80C), ₹50,000 for extra NPS and ₹2 lakh for self-occupied home-loan interest. Salary: employee and employer PF at 12% of basic (or of the ₹15,000 wage ceiling), gratuity at 4.81% of basic, and state professional tax. Capital gains: equity STCG at 20%, equity LTCG at 12.5% above ₹1.25 lakh, other long-term gains at 12.5%. HRA: the least of HRA received, rent minus 10% of basic + DA, and 50% (listed cities) or 40% of basic + DA.

Not included: surcharge on income above ₹50 lakh, loss set-off and carry-forward, deductions not listed in a calculator, and TDS timing.

United States

Tax year 2026. Included: federal brackets and the standard deduction for single, married filing jointly and head of household; Social Security at 6.2% up to the $184,500 wage base; Medicare at 1.45% plus 0.9% Additional Medicare above the threshold; pre-tax 401(k) and health deductions; self-employment tax on 92.35% of net profit with the half-SE-tax and QBI deductions; supplemental (bonus) withholding at 22% or by the aggregate method, with 37% above $1 million. State income tax: simplified California and New York brackets, or a flat rate you choose.

Not included: tax credits (such as the Child Tax Credit), itemized deductions, newer deductions for tips, overtime or seniors, local and city income taxes, and extra W-4 withholding. Sales tax uses each state's base rate plus a local rate you enter.

United Kingdom

Tax year 2026/27. Included: the £12,570 Personal Allowance and its taper above £100,000; rest-of-UK and Scottish income tax bands; Class 1 employee National Insurance; salary-sacrifice pension contributions; and student loan repayments for Plans 1, 2, 4 and 5 and Postgraduate Loans.

Not included: tax codes other than 1257L, benefits in kind, Marriage Allowance, savings and dividend income, and the High Income Child Benefit Charge.

Canada

Tax year 2026. Included: federal brackets; Ontario, British Columbia, Alberta and Quebec brackets and basic personal amounts; the federal BPA phase-out; the Canada employment amount; CPP/QPP (including CPP2/QPP2), EI and QPIP, with base contributions and premiums as credits and enhanced contributions as a deduction; Ontario surtax and Health Premium; the Quebec federal abatement; and RRSP room at 18% of prior-year earned income up to the annual limit.

Not included: other provincial credits and reductions (such as the Ontario tax reduction and Quebec's deduction for employment income), so Quebec results in particular are approximate; and pension adjustments that reduce RRSP room.

Rounding

We calculate with full precision and round only what we display: to the nearest rupee, dollar or pound for income tax tools, and to the cent for sales tax and bonus withholding. Totals may differ from the sum of rounded lines by one unit.

How we keep rates current

When a budget, finance act or annual indexation changes a figure, we update the relevant data file, record the official source next to it, and run our automated tests, which use worked examples calculated by hand from the official rules. Nothing ships unless every test passes. Each change is logged with its date on the updates page, and every calculator shows the date its figures were last checked.

Limitations

These tools are for estimates and planning. They are not tax, legal or financial advice. For decisions about your own return, consult a qualified professional. See our disclaimer.