Editorial standards

Calculators are only useful if you can trust the numbers. This page explains who is responsible for Calc Angel, how calculators are researched, built, reviewed and kept up to date, and what happens when we get something wrong.

Who is responsible

Calc Angel is written, programmed and maintained by Steve Davis (Founder & Editor), and published by Helium22 - www.helium22.com. One person is accountable for every formula on the site — there is no anonymous or automatically generated content. You can reach the editor directly through the contact page.

We are practitioners, not regulated advisers: nothing on this site is accounting, tax, legal, financial or medical advice. Where a calculator touches a specialist area — statutory pay, health measurements, structural materials — the page says so plainly and points you to the professional you should speak to.

How calculators are researched and built

  • Primary sources only for statutory figures. Tax bands, National Insurance thresholds, student-loan thresholds, statutory pay rates and bank-holiday dates are taken from GOV.UK, HMRC and the other official sources listed in each calculator's Sources & verification section — never from other calculator websites.
  • Formulas are published, not hidden. Every calculator page shows the exact formula it uses and a worked example you can reproduce by hand.
  • Engines are tested against official examples. The UK PAYE engine behind our salary calculators is verified against hand-computed cases, including edge cases such as the £100,000 personal allowance taper and the Scottish bands.
  • Assumptions are disclosed. Where a model simplifies reality (and every model does), the assumptions and the groups or situations it does not fit are listed on the page.

Calculation review policy

Each calculator page displays the date its formula and figures were last verified. Reviews happen:

  • Annually as a minimum — every calculator is re-checked at least once a year;
  • At each statutory change — salary, tax, VAT and statutory-pay calculators are re-verified before the start of each UK tax year and after fiscal statements that change rates;
  • Immediately on an error report — see the corrections policy below.

Time-sensitive calculators state the period their figures apply to (for example, "UK tax year 2026/27") so you can see at a glance whether the rules shown are the ones that apply to you.

Corrections policy

If a published formula, threshold or worked example is wrong, fixing it takes priority over all other work on the site. When you report a suspected error:

  • we re-derive the calculation by hand against the primary source;
  • confirmed errors are corrected in one place, server-side, which fixes the calculator immediately for every visitor and every site that embeds it;
  • we reply to tell you what we found, whether or not we changed anything.

We treat a discrepancy between a page's published formula and the calculator's actual output as a serious bug, not a cosmetic issue.

Update schedule

  • April (start of the UK tax year): full re-verification of all salary, tax and statutory-pay calculators against the new year's published rates.
  • After UK fiscal statements: check for in-year changes to VAT, interest and thresholds.
  • January: refresh of bank-holiday data and date tools for the year ahead.
  • Rolling: construction, health and conversion calculators re-checked against their sources at least annually.

Advertising and independence

The site is free to use and is funded by clearly labelled advertising and affiliate partnerships. Advertisers have no influence over formulas, defaults or editorial content, and no calculator result is ever altered to favour a commercial partner.

Read the methodology Report an error