Editorial Policy: How We Check Our Figures

Every calculator and guide on RightSums shows where its figures come from and when they were last checked. This page explains who is responsible, where our figures come from, how we keep them current, how we test calculations and how we use AI.

Who is responsible

Dany (RightSums team) is responsible for the content on RightSums, including checking that its figures match their sources.

Where our figures come from

• UK: GOV.UK and HMRC for Income Tax, National Insurance, student loans, tax codes, the minimum wage, redundancy and employer rates; the ONS for typical earnings; Ofgem for the energy price cap; NHS Employers and the NHS Business Services Authority for NHS pay and pensions; and the Department for Education and Teachers' Pensions for teacher pay.
• US: the IRS and the Social Security Administration for federal tax and payroll figures, the Tax Foundation's annual tables for state income tax, and the Department of Labor for overtime rules.
• Canada: the Canada Revenue Agency and Revenu Québec for tax and payroll, Service Canada for CPP, OAS and GIS, and IRCC and WelcomeBC for immigration points.
• Health: the NHS, EFSA, the US National Academies, Diabetes UK, the American Diabetes Association and the CDC, and published research such as the ADAG study.
• Home and building: Approved Document K, the International Residential Code and Canada's National Building Code for stairs, and US state transport department figures for material densities. Appliance running costs use Which? test results and the Centre for Sustainable Energy's power ratings.

When two sources disagree, we say so on the page rather than quietly picking one.

How we keep them current

Each figure lives in one place in our code, so a change updates every calculator and page that uses it. We keep a refresh calendar listing every figure that changes, its source and when it next needs checking: UK tax figures before each tax year starts on 6 April, the Ofgem price cap and Canada's OAS and GIS rates each quarter, US federal figures each autumn and state tables each winter, pay awards when they are published, and immigration points whenever the rules change. A weekly check flags anything that is due, and each page shows the date its figures were last checked.

How we test calculations

Tax, totals, conversions and estimates are worked out with fixed formulas that you can see on the page. Before a tool goes live we check its results against hand-worked examples and, where they exist, the worked examples published by the source, such as HMRC, the Canada Revenue Agency or Ontario's guide to employment standards. Where a result depends on an assumption, such as a 37.5-hour week or a standard tax code, the page says so.

How we use AI

We use AI tools to help research sources, draft pages and write code. AI does not decide any figure: every rate, threshold and rule is checked against its official source, and every calculation is tested, before it is published. Your results are not worked out by AI; the calculators use fixed formulas in your browser or on our server.

Reading documents

The business document tools read PDFs, spreadsheets and Word files with our own parser. When our Google Gemini integration is switched on, a scanned file or a table our parser cannot read may be sent to Gemini to transcribe it, as set out in our privacy policy. Extracted figures are always shown to you to check before you rely on them.

Corrections

If a figure looks wrong, we check it against its source, correct the page and update the date it was checked.

Tell us by emailing support@rightsums.com.

Our tools give estimates to help you plan. They are not financial, tax, legal or medical advice.