This page explains how the Tools Veria editorial team researches, builds, checks and updates the calculators and guides on this website. It applies to every tool and every article we publish. Last reviewed: October 2026.
The Sources We Use
We take rates, thresholds and allowances from the organisation that sets them, not from other calculators or news reports. The main sources are:
| Topic | Primary source |
|---|---|
| UK income tax, National Insurance, dividends, VAT, mileage rates | HMRC and GOV.UK |
| Statutory pay: maternity, sick, redundancy, holiday | GOV.UK guidance and the relevant legislation |
| Irish tax and VAT | Revenue |
| Energy prices and the price cap | Ofgem |
| Inflation and earnings data | Office for National Statistics |
| Interest rates and the inflation target | Bank of England |
| Units and conversion factors | Internationally agreed SI definitions and UK weights and measures law |
Where a figure changes often and no official value exists, such as the price of petrol, a share price or a lender’s interest rate, we do not claim a “current” number. Instead the tool shows an editable example value and tells you to enter your own.
How We Test Calculations
- Each formula is written out and checked against the official method before it goes into the tool.
- We run worked examples by hand, including edge cases such as earnings just over a threshold, a zero input or a very large value, and the tool must match them.
- Where an official calculator exists, for example on GOV.UK, we compare our results with it.
- We test every tool on mobile and desktop browsers before it is published.
Keeping Figures Up to Date
Each tax and benefit tool states the tax year it applies to. We review these tools before 6 April each year, energy tools whenever Ofgem announces a new quarterly price cap and inflation tools when the ONS publishes new consumer price index figures. Guides are updated at the same time, and the “Updated” date on each article shows when it last changed.
How We Use Software and AI
We use software to help us work faster, including AI writing assistants for drafting and formatting text and scripts for building and testing tools. Software never has the final say. Every rate and threshold is checked against its official source, every calculation is tested against worked examples, and every guide is reviewed for accuracy and plain English before it is published.
Independence
No company pays to appear in our tools or to influence what we write. We do not recommend specific banks, lenders, energy suppliers or investments. If we ever show advertising or use affiliate links, they will be clearly labelled and kept separate from the results our tools produce.
Corrections
If you think a figure, formula or statement is wrong, please tell us through our contact page and include the page address. We check every report against the official source. Confirmed errors are corrected as soon as possible, normally within two working days, and significant corrections to a guide are noted on that page.
You can read more about who we are on our About page and about the limits of our tools in our disclaimer.