Add sales tax to a price before you buy, or strip the tax out of a receipt total to find the original price. The same maths works for VAT and GST.
Formula
Total = Price × (1 + Rate ÷ 100)
To remove tax, divide instead: Price = Total ÷ (1 + Rate ÷ 100). Subtracting the rate from the total is a common mistake that gives the wrong answer.
Worked example
$100 with 8.25% tax costs $108.25. Working backwards, $108.25 ÷ 1.0825 = $100.
Frequently asked questions
How do I calculate sales tax?
Multiply the price by the tax rate as a decimal. 8% of $50 is 50 × 0.08 = $4, so you pay $54.
How do I find the price before tax?
Divide the total by 1 plus the tax rate as a decimal. With 20% VAT, a £120 total is £120 ÷ 1.2 = £100 before tax.
Last updated · Calculations checked by automated tests· Editorial policy