VAT Calculator
Add VAT to a net amount or remove VAT from a gross amount.
About this calculator
This VAT calculator works in both directions: add VAT to a net figure to get the gross amount for an invoice, or remove VAT from a gross figure to find the net amount and the tax within it. The remove direction is the one people get wrong — you cannot simply knock 20% off a gross price, because the VAT was added to the smaller net figure, not the larger gross one.
The default rate is the UK standard 20%, but you can enter any rate, including the UK reduced rate of 5% or another country's rate.
The formula
Worked example
A gross receipt shows £120 including 20% VAT.
- Net = £120 ÷ 1.20 = £100
- VAT = £120 − £100 = £20
Note that subtracting 20% of £120 (£24) would give the wrong answer.
Common mistakes
- Removing VAT by subtracting the percentage from the gross amount instead of dividing.
- Using the standard rate on goods that are reduced-rated or zero-rated.
- Quoting consumers net prices — consumer-facing prices must normally be shown including VAT.
Frequently asked questions
Assumptions & limitations
This is an arithmetic tool, not tax advice. Rates and category rules change — confirm anything material with HMRC or your accountant.
Sources & verification
- VAT rates — GOV.UK — standard, reduced and zero rates
All sources last accessed 24 July 2026.
Spotted an error or an out-of-date figure? Report it — corrections are prioritised over all other work (see our corrections policy).