VAT / GST CALCULATOR
Add or remove VAT or GST using your own tax rate. Calculate net, tax and gross amounts, see the reverse-tax formula and export the breakdown.
THE CLEARER PICTURE
Enter your details or try the example to see how it works.
A LITTLE CONTEXT GOES A LONG WAY
Choose Add tax if your starting amount excludes tax, or Remove tax if it includes tax. Enter one rate for that amount. The currency controls the number format and rounding; it does not identify the applicable country, tax treatment or registration status.
To add tax: tax = net × rate ÷ 100, then gross = net + tax. To remove tax: tax = gross × rate ÷ (100 + rate), then net = gross − tax. With an illustrative 20% rate, 100 net becomes 120 gross. Working backwards from 120 gives 20 tax and 100 net. Subtracting 20% of 120 would give the wrong result.
The tax component rounds once to the currency’s smallest unit, and the other amount is the remainder. Net plus tax always equals gross. Separate calculations for multiple lines can round differently from one calculation on the total. Use your invoice’s required method and separate amounts that have different tax rates.
Formula reference: HMRC: adding and removing VAT ↗. Rates and treatment depend on your transaction.
Created by Ostro. Read our editorial standards or report a correction. The guide above explains the method, assumptions and examples.
GOOD TO KNOW
No. You supply the rate. The tool performs single-rate arithmetic; it does not determine registration, exemptions, place of supply, reverse-charge treatment or recoverable tax.
Yes. Choose Remove tax, enter the gross price and the rate. The tool divides by the tax-inclusive factor rather than subtracting the rate directly from the gross price.
The tax amount is zero and net equals gross. A zero-rate calculation alone does not establish that a sale is zero-rated or exempt.
No. These tools work in this open page. Nothing is uploaded or stored, and refreshing clears your entries. Export the results you need before leaving.
