Add it. Remove it. Know exactly where it landed.
Enter an amount, pick a rate, and see the net, VAT and gross breakdown instantly — works as a normal VAT calculator or a reverse VAT calculator.
Want a proper desk calculator to go with this?
A printing calculator with a paper tape makes reconciling a stack of receipts far quicker than typing into a phone.
What's a reverse VAT calculator?
A reverse VAT calculator works backwards from a price that already includes VAT, splitting it back into the net amount and the VAT itself — handy when you've got a VAT-inclusive figure from a receipt or invoice and need to know what it looked like before VAT was added. Switch to Remove VAT in the calculator above to use VatFlip this way: enter the gross amount, pick the rate, and it shows the net and VAT portions instantly.
How to calculate VAT
The calculator above does this for you, but here's the arithmetic behind it — useful when you need to check a figure by hand.
Adding VAT
The calculation for adding VAT is:
- Multiply the net amount by the VAT rate to find the tax
- Add that tax back onto the net amount to get the gross total
£100 × 0.2 = £20
This gives you a VAT amount of £20 and a gross total of £120.
Removing VAT
To remove VAT you calculate:
- Divide the total (gross) amount by 1 plus the VAT rate to get the net value
- Subtract that net figure from the gross to find the VAT
£100 ÷ 1.2 = £83.33
This gives you a net total of £83.33, with the remaining £16.67 as VAT.
At the 5% reduced rate the same method applies — multiply by 0.05 to add it, or divide by 1.05 to remove it.
VAT calculation questions
The three that trip people up most often when working with VAT-inclusive figures.
Why doesn't taking 20% off a gross price give the right net figure?
Because the 20% was added to the net amount, not the gross one — so taking 20% off the gross deducts more than was added in the first place.
On a £120 gross price, the VAT is £20, not £24. Taking 20% off £120 would leave £96, which is wrong. Dividing by 1.2 gives the correct £100 net.
What's the quick way to find just the VAT in a VAT-inclusive price?
At the 20% standard rate, the VAT is exactly one sixth of the gross figure — so divide by 6. On £120 gross that's £20 of VAT.
At the 5% reduced rate the shortcut is one twenty-first of the gross, though dividing by 1.05 and subtracting is easier to remember.
Which VAT rate should I use in the calculator?
Most goods and services are standard-rated at 20%. A reduced rate of 5% applies to things like domestic energy and children's car seats, and a 0% zero rate covers most food and children's clothes.
If you're unsure which applies to what you're selling, HMRC publishes a rate-by-category list. The custom rate option is there for historic rates or non-UK calculations.
More than a calculator
A full reference for the codes behind the numbers, and regular posts digging into the detail.
Nominal Codes Glossary
Every standard Sage nominal code explained — what it's for, its category, and its normal debit/credit balance.
Blog
Monthly deep-dives into specific nominal codes — the debits, the credits, and worked examples.
VAT FAQs
When you can charge VAT, when you have to register, and what zero-rated really means.
Understand VAT itself
Background reading that comes up in most VAT searches — what it is, how it changed, and one popular way small businesses simplify it.
What Is VAT? A Plain-English Explanation
Output and input tax, who has to register, and the three UK rates.
The Flat Rate VAT Scheme Explained
How the scheme works, who can join, and how the percentages are set.
The History of VAT in the UK
From Purchase Tax in 1973 to the 20% standard rate of today.
Why VatFlip
VatFlip started as a way to stop switching between a calculator and a chart of accounts just to check a VAT figure or look up what a nominal code means. The calculator above runs entirely in your browser — nothing you type is sent anywhere — and the nominal codes glossary and blog cover the reference material that usually lives in a separate spreadsheet. It's an independent site, not affiliated with Sage (UK) Limited. Read more about VatFlip →