How to use it
Type the amount. It is currency-neutral, so 100 means 100 pounds, euros, rupees or dollars depending on what you had in mind, and no symbol appears anywhere in the output.
Now the rate. Either type it, press one of the 5%, 17% and 20% buttons, or use the country dropdown, which sets the rate and then clears itself so it never argues with a figure you typed by hand.
Then say what your amount already is. Add VAT (amount is net) treats it as a price before tax. Remove VAT (amount is gross) treats it as a price with the tax already inside.
Three cards read out net, VAT amount and gross. A pie chart splits net against VAT underneath them, a note tells you which direction was applied, and everything recalculates on every keystroke, so there is no button to press and no results to wait for. Leave the rate blank and it behaves as 0%.
The two sums
Adding is the easy direction. VAT is the net times the rate, and gross is the net plus that, so a net of 100 at 20% gives 20 of VAT and a total of 120.
Removing is where people go wrong. You cannot take 20% off the gross, because the 20% was never charged on the gross in the first place. It was charged on the smaller net figure sitting underneath it.
Divide instead. Gross over 1.20 gives the net, and the VAT is whatever is left. So 120 divided by 1.20 is 100 net and 20 of VAT, whereas 20% of 120 comes to 24, which is 4 too much and would have you reclaiming tax that was never charged.
HMRC keeps a shortcut for this. It is called the VAT fraction: the rate over 100 plus the rate, cancelled down. At 20% that works out as 20/120, which is one sixth, so a sixth of any gross price is the VAT inside it. The fraction is 1/21 at 5%, and at the old 17.5% rate it was the famously awkward 7/47.
You are allowed to round the VAT down
Most calculators round to the nearest penny and leave it there. UK VAT rules are stranger than that.
Paragraph 17.5 of VAT Notice 700 lets you round the total VAT payable on all the goods and services shown on a VAT invoice down to a whole penny, ignoring any fraction of a penny. Not to the nearest penny. Down.
The catch is who it applies to. HMRC's own manual, VATREC12010, calls this a concession designed for invoice traders, and it works because the effect is tax-neutral: whatever the supplier knocks off its output tax, the customer knocks off its input tax to match.
Retailers do not get it. Round down the VAT charged to a final consumer and nobody claims that penny back, so the only thing that shrinks is the amount reaching HMRC. VATREC12020 sets out what retailers on normal accounting may do instead: use a published retail scheme, round up and down to the nearest 1p, or calculate to at least five decimal places and round to four.
Worth knowing before you argue with an accounts system over a penny. Also worth knowing that both flavours of rounding are legitimate, which is why two correct invoices for the same order can differ by 1p.
VAT and GST are the same arithmetic
The label changes with the border. Europe and the UK say VAT. Australia, India, New Zealand, Singapore and Canada usually say GST. India also splits its GST into central and state halves on domestic sales, but the total percentage is what lands on the invoice, and that total is what this calculator wants.
So type 10 for Australian GST, 15 for New Zealand, 18 for a common Indian slab, 20 for standard UK VAT. Nothing about the maths changes.
One warning about the Canada entry in the dropdown. The 5% there is the federal GST on its own, which is the whole story only in Alberta and the three territories. Five provinces charge a single harmonised rate instead: Ontario is 13%, Nova Scotia has been 14% since 1 April 2025, and New Brunswick, Newfoundland and Labrador and Prince Edward Island are all 15%. Quebec stacks a 9.975% QST on top of the GST for an effective 14.975%. Type the combined figure rather than the 5%.
Which rate applies
Standard rates in the EU cannot drop below 15%. Article 97 of Directive 2006/112/EC sets that floor and sets no ceiling at all, which is how Hungary reached 27% while Luxembourg sits at 17%.
Nearly every country then runs reduced rates underneath the standard one. Books, children's clothes, domestic fuel, food, public transport: the lists differ everywhere and they are not intuitive, so check the rate for the specific thing you are selling rather than assuming the headline number.
The UK moved to 20% on 4 January 2011, up from 17.5%, and has stayed there since. The 5% quick-pick covers the UK reduced rate on things like domestic energy and children's car seats.
What it is good for
Quoting a client a net fee and needing the all-in number to put on the email, or on an invoice. Reading a receipt that shows only a gross total and working out how much of it was tax. Splitting a VAT-inclusive expense into net and VAT for the books. Starting from a shelf price you have already committed to and finding what you actually keep. For discounts, markups and anything else that is not a tax, the percentage calculator is the better fit.
Frequently asked questions
How do I add VAT to a net price?
Pick "Add VAT (amount is net)", enter the price and the rate. The calculator multiplies the price by the rate to get the VAT and adds it on. At 20% on 100 that is 20 of VAT and 120 gross.
How do I remove VAT from a gross price?
Choose "Remove VAT (amount is gross)" and enter the VAT-inclusive figure. It divides by 1 plus the rate to recover the net, then shows the VAT that was sitting inside. A gross of 120 at 20% gives 100 net and 20 VAT.
Why can I not just take 20% off a gross price?
Because the 20% was charged on the net, not the gross. Take 20% of a 120 gross and you get 24, which overstates the VAT by 4. Divide by 1.20 instead and you land on the correct 100 net.
Is VAT the same as GST?
For this calculator, yes. Both are a flat percentage of a price, so the arithmetic is identical and only the name and the number change. Type whichever rate applies where you are trading.
Does it handle rates like 7.5% or 17.5%?
Yes. Amount and rate both accept decimals, so odd rates and prices like 19.99 are fine. Figures display to two decimal places, with trailing zeros dropped, so a result of exactly 120 shows as 120 rather than 120.00.
Which currency does it use?
None. It works on the plain numbers you type, so net, VAT and gross all come back in whatever currency you had in mind. The dollar sign on the pie chart is a display placeholder only.
Is the calculator private?
Yes. The whole thing runs in your browser with JavaScript. The amounts and rates you enter are not sent anywhere.
Results are rounded for display; for invoices, filings or accounting, double-check critical figures against the current official rate.