Methodology

This page explains exactly how our numbers are produced, so you can judge them for yourself.

1. One shared tax engine

Every calculator on the site calls the same 2026/27 tax engine. It covers income tax bands for England, Wales, Northern Ireland and Scotland, employee National Insurance, student loan Plans 1, 2, 4 and 5 plus the postgraduate loan, and auto-enrolment pensions. The engine is unit-tested against hand-computed band boundaries. The full model, in plain English, lives on the 2026/27 tax guide — individual calculator pages link to it rather than repeating it.

2. Real pay datasets, named and dated

Pay figures come from published sources, never from guesswork. Our HGV figures come from the RHA Pay Report 2026 (surveyed October– November 2025), cross-checked against the Aspion 2026 salary guide, Jooble advertised rates (July 2026) and ONS ASHE (November 2025). Armed forces pay comes from the AFPRB 55th Report 2026. Each page lists its sources with access dates.

3. Estimates are labelled as estimates

Where a published source gives a range and the calculator needs a point — for example, interpolating between published pay-scale anchors, or converting a daily allowance to an annual figure — the result is labelled an estimate and the verified range is shown alongside. We never present an interpolated number as a published fact.

4. Reviewed every April

Every page carries a review stamp. We re-verify figures each April, when the new tax year, the AFPRB award and the RHA pay report land, and bump the stamp. If a figure goes stale between reviews, the stamp tells you — we would rather show our working than pretend.

5. Old numbers carry their date

Some widely quoted figures are out of date — the 2021-era HGV driver shortage numbers are the classic example. Where we mention an older figure, it carries its date as a caveat. Current framing uses the Logistics UK Q2 2026 tracker and RHA April 2026 figures.