What this site is
UK VAT Calculator is a free online tool that converts prices between net (excluding VAT) and gross (including VAT). It supports the UK standard rate of 20%, the reduced rate of 5%, the zero rate, and any custom rate — useful for old invoices from when the standard rate was different, or for one-off calculations.
The site is built for the people who do this sum every week: freelancers preparing invoices, traders pricing jobs, online sellers checking margins, bookkeepers splitting receipts, and shoppers who simply want to know how much of a price is tax.
How it works
- Everything runs in your browser. The figures you type are never sent to a server, stored, or shared.
- There is no sign-up, no fee and no download — the calculator works the moment the page loads.
- The maths follows the standard formulas HMRC describes: adding VAT means multiplying the net by (1 + rate), and removing VAT means dividing the gross by (1 + rate).
What this site is not
UK VAT Calculator is an independent tool. It is not affiliated with HMRC or GOV.UK, and it is not a substitute for professional tax advice. VAT rules have exceptions for specific industries and situations; for anything beyond a straightforward net/gross conversion, confirm your figures with your accountant or with HMRC directly.
Accuracy
Results are calculated to the penny using standard rounding. Very large or unusual figures — for example, invoices combining several VAT rates — should be checked line by line, as rounding each line separately can differ by a penny from rounding the total.
Found an error or have a suggestion? We would genuinely like to hear it — see the contact page.