Methodology & Sources
Last updated: September 2026
TaxYourSalary is a calculator, so the only thing that matters about it is whether its numbers are right and whether you can tell where they came from. This page sets out both: which official body publishes the rates each market uses, when we last compared our figures against those published rates, how the take-home figure is assembled, and — just as importantly — what the result does not include.
Where the tax rates come from
Every rate in the engine comes from a primary source: the revenue authority or the statute itself. We do not take rates from other calculators, from news summaries or from third-party rate aggregators, because those are where transcription errors live. The table below lists the body that publishes each market’s rates, the page the figures were read from, the tax year they apply to, and the date the figures were last checked.
| Market | Rates published by | Tax year | Last checked |
|---|---|---|---|
| United Kingdom | HM Revenue & Customs (HMRC)Income tax bands and the personal allowance, plus National Insurance for employees from GOV.UK's own rates pages. | 2026/27 | 19 September 2026 |
| United States | Internal Revenue Service (IRS)Federal brackets and the standard deduction (Revenue Procedure 2025-32). Social Security and Medicare come from the Social Security Administration; each state's schedule comes from that state's own revenue department. | 2026 | 19 September 2026 |
| Canada | Canada Revenue Agency (CRA)Federal brackets and the basic personal amount, plus CPP and EI from canada.ca's published 2026 rates. Provincial tax on this site is calculated on Ontario's schedule. | 2026 | 19 September 2026 |
| Australia | Australian Taxation Office (ATO)Resident income tax brackets and the Medicare levy from the ATO's published resident rates. | 2026-27 | 19 September 2026 |
| Ireland | Revenue Commissioners (Revenue)The single standard rate band (€44,000 for 2026), the 20% and 40% rates, personal tax credits and the Universal Social Charge. | 2026 | 19 September 2026 |
| Germany | Bundesministerium der Finanzen (BMF) / §32a EStGThe §32a Einkommensteuergesetz tariff for Veranlagungszeitraum 2026 (the official statute text) and the BMF's Programmablaufplan 2026; social-insurance contribution ceilings from the 2026 Rechengrößen. | 2026 | 19 September 2026 |
| France | Direction générale des finances publiques (DGFiP)The income tax barème (bracket thresholds and rates) published for the 2026 tax calculation, and the décote. | 2026 | 19 September 2026 |
| Spain | Agencia Estatal de Administración Tributaria (AEAT) / Seguridad SocialThe AEAT's 2026 withholding algorithm for employment income (the article 20 reduction and the state-plus-regional scale) and Seguridad Social contribution rates for 2026. | 2026 | 19 September 2026 |
| Netherlands | BelastingdienstBox 1 brackets and rates for 2026 and the heffingskortingen (the general and labour tax credits). | 2026 | 19 September 2026 |
| India | Income Tax Department, Central Board of Direct Taxes (CBDT)New-regime slab rates under section 115BAC, the ₹75,000 salary standard deduction, the section 87A rebate and the 4% health and education cess; the EPF employee contribution rate. | AY 2026-27 | 19 September 2026 |
These ten markets are the ones with a written provenance record. For markets not listed above, the rates used are the published national rates for 2026, but we have not recorded an official source for them on this page — that is a gap in our documentation, not a claim that the figures are unsourced. If you are relying on a market that is not in the table, treat the result as a first approximation and confirm it against the authority directly.
How the take-home figure is calculated
Each market runs its own function in the tax engine rather than sharing one generic formula, because deductions differ structurally between countries. Broadly, a calculation works through four steps:
- Apply the standard deduction or allowance first. Most markets let a fixed slice of income go untaxed before the brackets apply — the UK personal allowance, the US standard deduction, Canada’s basic personal amount, Ireland’s tax credits, India’s ₹75,000 salary standard deduction.
- Walk the progressive bands. Each band is charged at its own rate, so the marginal rate only applies to the slice of income inside that band, not to the whole salary. That is why the effective rate on the results page is lower than the headline rate.
- Add the payroll contributions. National Insurance, FICA, CPP and EI, social security, EPF — whichever apply — are calculated on their own wage base and ceiling, separately from income tax.
- Subtract credits and apply reliefs. Non-refundable credits, the Dutch heffingskortingen, Spain’s article 20 reduction, the section 87A rebate: these reduce the tax itself rather than the income it is charged on.
The subtraction is arithmetic, and the arithmetic happens in your browser. Nothing you type into a calculator is sent to us — see the privacy policy for that side of it.
How often the figures are checked
Rates are reviewed when a source changes them, which in most markets means around the annual Budget or the start of the tax year. The "Last checked" column above records the date our engine was last compared, figure by figure, against the publisher’s own page or the statute. A date there is a record of an actual comparison — we do not stamp a fresh date on a page without re-reading the source. Where a rate is changed by a source we can obtain, we update the engine rather than the marketing copy, so the calculator and the text around it cannot disagree.
What the result includes — and what it does not
The models describe a single earner on a straightforward salary with no dependants and no special circumstances. That means the following are generally outside the calculation:
- Deductions and credits you claim personally — pension contributions beyond the standard model, student loan repayments, salary sacrifice, charitable giving, childcare, mortgage interest relief.
- Household effects: marriage allowances and income splitting, child benefit and family credits, joint or separate assessment.
- Sub-national variation, except where stated. US federal tax plus one state schedule; Canada uses Ontario; local and municipal taxes, cantonal and regional add-ons, and city-level surcharges are not modelled.
- Income that is not salary — self-employment, dividends, rental income, capital gains — and the interaction between them.
- Anything retroactive. If a rate was changed mid-year, the result reflects the annualised published rate, not a blended actual.
Estimates, not advice
Every figure on this site is an estimate for general information. It is not tax, legal, accounting or financial advice, and it is not a substitute for a payroll calculation, a tax return or a professional opinion on your own circumstances. Tax law changes, and individual situations vary in ways no calculator can capture. Before you make a decision that turns on a number from this site — a job offer, a relocation, a repayment plan — confirm it with the revenue authority named in the table above or with a qualified adviser.
Finding an error, and what happens next
If a rate or a deduction on this site looks wrong, tell us. Corrections are the most useful message we get: they are checked against the official source, and if the source confirms the problem, the engine is fixed and the market’s check date is updated. Include the market, the salary you used, the figure you expected and the link you compared it against, and send it through the contact page.
Getting a figure wrong and being told about it is how the calculator improves.