Methodology & data sources

Last updated: 21 June 2026

Many Gera Tools tools rely on published reference data — tax bands, official thresholds, average costs and statistics. This page explains where that data comes from, how we compute results, and how often we refresh it. Every data-backed page also shows its own source and "as of" date inline, so you can always see what a specific result is based on.

How results are computed

Calculators run entirely in your browser using transparent formulas — the same formulas we show on the page. We do not estimate or invent figures: a result is either computed from your inputs and published rates, or, where a required figure isn't reliably available, the tool says so rather than guessing. Worked examples are labelled as illustrative.

Primary data sources

We take reference figures from authoritative primary sources, including:

• UK government & statistics: GOV.UK, HM Revenue & Customs (HMRC), the Office for National Statistics (ONS), the Department for Work & Pensions (DWP), NHS Digital / NHS England, the Department for Education (DfE), DEFRA, the Land Registry, and the Bank of England — under the Open Government Licence v3.0.
• US federal sources (public domain): the Internal Revenue Service (IRS), the Bureau of Labor Statistics (BLS), the US Census Bureau, the Centers for Medicare & Medicaid Services (CMS), the Centers for Disease Control and Prevention (CDC), FEMA, and the FHFA.
• Industry & clinical reference: established datasets such as Bankrate / LodeStar for US housing and closing-cost averages, and EUCAST / CLSI for clinical microbiology reference. Clinical tools are reference aids only and are not a substitute for professional judgement.

Update cadence

Annual figures (such as tax bands, contribution limits and benefit rates) are updated when the relevant authority publishes the new tax or fiscal year. Periodic statistics (such as average costs, wages, and survey-based figures) are refreshed on their publication schedule. Each page carries the source and the "as of" date for its figures, so you can confirm currency at a glance.

Accuracy & corrections

We work hard to keep every figure correct and traceable to a named source, but errors are always possible. If you find a mistake in any tool, rate table or reference figure, please tell us via the Contact page — include the tool name or page link and what you expected — and we will investigate and correct it. Gera Tools is operated by Gera Systems Ltd (United Kingdom).

Tools and reference content are provided for general information. For decisions with financial, legal, medical or safety consequences, verify the result and seek appropriate professional advice — see our Disclaimer.