Sales Tax / VAT / GST Calculator
Add tax to a price or back it out of a gross total, with one-click presets for common UK, EU, Australia, Canada and other rates. Rates are approximate — confirm the current figure for your region.
Open the free Sales Tax / VAT Calculator →How it works
There are two everyday jobs this tool handles. Adding VAT or sales tax takes a net, tax-exclusive price and grosses it up: multiply by 1 + rate. At a 20% rate that means multiplying by 1.20, so a net price of 100 becomes a gross price of 120 and the tax is 20. This is what the add VAT calculator mode does the moment you pick a preset or type a rate.
Reversing VAT or sales tax does the opposite: it pulls the tax out of a gross, tax-inclusive total. Divide the gross price by 1 + rate to find the net amount, then subtract to reveal the tax. For a 120 gross at 20%, the net is 120 / 1.20 = 100 and the VAT is 20. A reverse VAT calculator (or reverse sales tax calculator) is what you need when a client quotes you an all-in figure and you have to split out the tax for your invoice or bookkeeping.
VAT, GST and US-style sales tax all use the same arithmetic — only the convention differs. VAT and GST prices are often quoted inclusive of tax, while US sales tax is usually added at the till and quoted exclusive. Choose add or reverse mode to match how the price was given to you.
Worked example
Say a UK client agrees a project fee of 1,000 net and you charge 20% VAT. In add mode: 1,000 × 1.20 = 1,200 gross, of which 200 is VAT that you collect and pass on.
Now imagine instead the client says “we have a budget of 1,200 including VAT.” Use reverse mode: 1,200 / 1.20 = 1,000 net for you, and 1,200 − 1,000 = 200 VAT. Same numbers, opposite direction — which is exactly why having both add and reverse in one calculator saves you from second-guessing the formula.
Frequently asked questions
- How do I add VAT to a price?
- Multiply the net (tax-exclusive) price by 1 plus the rate as a decimal. For 20% VAT, multiply by 1.20. A net price of 100 becomes a gross price of 120, where 20 is the VAT. The add VAT calculator does this for you with one-click presets.
- How does a reverse VAT calculator work?
- A reverse VAT calculator backs the tax out of a gross (tax-inclusive) total. Divide the gross price by 1 plus the rate to get the net amount, then subtract to find the VAT. For a 120 gross at 20%, net is 120 / 1.20 = 100 and the VAT is 20.
- What is the difference between VAT, GST and sales tax?
- VAT (value-added tax) and GST (goods and services tax) are charged at each stage of supply and are usually shown inclusive of the price in many countries. US-style sales tax is typically added at the point of sale and quoted exclusive. The maths is the same; only how the price is normally quoted differs, so use the add or reverse mode to match.
- How do I calculate the tax amount from an inclusive price?
- With a reverse sales tax calculator, take the tax-inclusive total and multiply by the rate divided by (1 plus the rate). For 20% the multiplier is 0.20 / 1.20 = 0.1667, so a 120 inclusive price contains 20 of tax. Alternatively divide by 1.20 to find the net and subtract.
- What VAT and sales tax rates does the calculator use?
- It includes one-click presets for common rates such as UK 20%, many EU standard rates around 19-25%, Australia GST 10% and Canada GST 5% (plus combined provincial rates). You can also type any custom rate. Presets are approximate, so confirm the current figure for your region before invoicing.
- Is the VAT calculator free and private?
- Yes. The calculator is free with no sign-up. All calculations run locally in your browser and nothing is uploaded, so your prices and figures stay on your device.