To add tax, multiply by 1 plus the rate; to take it out, divide by 1 plus the rate. At 20%, 100 net becomes 120 gross, and 120 gross contains 100 net plus 20 tax. Type the amount and your rate – it differs by country, state and product – and the calculator does either, showing the formula with your numbers.
Taking tax out: divide, don’t subtract
The most common mistake is to subtract the rate from the gross price. Subtracting 20% from 120 gives 96, but 96 + 20% is 115.20, not 120. The tax was calculated on the net price, so you have to divide to get back to it.
| Rate | To remove the tax, divide by | Tax as a share of the gross price |
|---|---|---|
| 5% | 1.05 | 4.76% |
| 7% | 1.07 | 6.54% |
| 8% | 1.08 | 7.41% |
| 10% | 1.10 | 9.09% |
| 13% | 1.13 | 11.50% |
| 15% | 1.15 | 13.04% |
| 18% | 1.18 | 15.25% |
| 19% | 1.19 | 15.97% |
| 20% | 1.20 | 16.67% |
| 21% | 1.21 | 17.36% |
| 22% | 1.22 | 18.03% |
| 25% | 1.25 | 20.00% |
The last column is useful when you only have a receipt: multiply the total by it to see how much tax you paid. At 20%, a bill of 54 contains 54 × 16.67% = 9.00 of VAT.
VAT, GST and sales tax
| Tax | How it works | Prices on the shelf |
|---|---|---|
| VAT / GST | Charged at every stage; businesses reclaim the tax on what they buy | Usually include the tax |
| Sales tax | Charged once, at the final sale to the consumer | Usually exclude the tax; added at the register |
Most countries use VAT or GST, often with a standard rate and one or more reduced rates for food, medicine or books. The US uses sales tax set by states and local governments instead. Because rates change and depend on the product, check the current rate with the tax authority where the sale takes place before you invoice.
Invoicing tips
- Show the net amount, the rate, the tax and the gross total on separate lines.
- Round the tax once, on the total, rather than line by line, unless your tax authority says otherwise; line-by-line rounding can shift the total by a cent or two.
- Selling across borders? The rate may depend on where your customer is, not where you are.
Prices, rates and amounts stay on your device; nothing is sent anywhere. Once zet4u is saved there, the calculator works offline too – on a trip abroad without data, for example.
Frequently asked questions
How do I add VAT to a price?
Multiply the net price by 1 plus the rate. At 20%: 100 × 1.20 = 120.
How do I remove VAT from a price?
Divide the gross price by 1 plus the rate – do not subtract the percentage. At 20%: 120 ÷ 1.20 = 100. Subtracting 20% from 120 would give 96, which is wrong.
What share of a gross price is VAT?
Rate ÷ (100 + rate). At 20%, VAT is 20 ÷ 120 = 16.67% of the price you pay. At 10% it is 9.09%.
Is GST the same as VAT?
They work the same way: a tax added at each stage of sale, with businesses reclaiming the tax they pay on inputs. Countries such as Australia, Canada, India and New Zealand call it GST.
Why does the US show prices without tax?
US sales tax is set by states, counties and cities, so the same item can be taxed at different rates a few miles apart. Shops show the price before tax and add it at the register.
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