How the calculation works
VAT is a percentage of the price without VAT. Adding it means multiplying, and taking it out means dividing by the same factor.
Including VAT = excluding VAT × (1 + rate ÷ 100)
Excluding VAT = including VAT ÷ (1 + rate ÷ 100)
VAT = including VAT − excluding VAT
The factor is 1.20 at 20%, 1.21 at 21% and 1.09 at 9%.Worked examples
Add VAT: 250 excluding VAT at 21%.
- The factor is 1 + 21 ÷ 100 = 1.21.
- 250 × 1.21 = 302.50 including VAT.
- The VAT is 302.50 − 250 = 52.50.
Remove VAT: 121 including VAT at 21%.
- 121 ÷ 1.21 = 100 excluding VAT.
- The VAT is 121 − 100 = 21.
What this calculator does not include
- Mixed rates on one invoice. Calculate each rate on its own.
- Rules for exemptions, reverse charge and sales to other countries.
- Rounding per invoice line. Amounts are rounded to cents for display only.
Amounts are rounded for display only; the calculation itself is not rounded. Results are estimates for information, not financial advice. Last updated: 12 November 2026.
Frequently asked questions
How do I add VAT to a price?
Multiply the price excluding VAT by 1 plus the VAT rate divided by 100. At 20%, 100 becomes 100 × 1.20 = 120, of which 20 is VAT.
How do I take VAT out of a price?
Divide the price including VAT by 1 plus the VAT rate divided by 100. At 20%, 120 becomes 120 ÷ 1.20 = 100, and the VAT is 20.
Why is taking 20% off the total the wrong way to remove VAT?
Because VAT is a percentage of the price without VAT, not of the total. 20% of 120 is 24, but the VAT in 120 is only 20.
Which VAT rate should I use?
It depends on the country and the product. For example the Netherlands has a standard rate of 21%, a reduced rate of 9% and a 0% rate. Check the rate that applies to you with your tax authority, and type it in the VAT rate field.
Does the calculator work for sales tax?
It does the same arithmetic as a simple sales tax added on top of a price. US sales tax differs by state and is not shown on the price, so enter the rate that applies to your purchase.