GST / VAT Calculator
Add or remove GST/VAT from a price.
Tax Amount
Total
Free to useNo software to install — works in any modern browser.
No signup neededOpen the tool and start straight away.
Runs in your browserNothing you enter is sent to a server.
Works on mobileSame tool on your phone, tablet or desktop.
How it works
- Enter — type or paste your values or text.
- Get the result — it is worked out in your browser.
- Adjust — change the inputs to compare, or copy the result.
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About GST / VAT Calculator
Add sales tax to a price, or work out how much tax is inside a price that already includes it. It runs in your browser and works for GST, VAT or any sales tax at any rate.
Adding tax
Price including tax = price before tax × (1 + rate ÷ 100). At an 18% rate, 1,000 becomes 1,000 × 1.18 = 1,180, of which 180 is tax.
Removing tax — the common mistake
To find the price before tax from 1,180, divide by 1.18 to get 1,000. Taking 18% off instead (1,180 × 0.82) gives 967.60, which is wrong, because the 18% was calculated on the smaller, pre-tax amount. This mistake is easy to make on invoices and receipts.
Which rate?
Rates differ by country and sometimes by product, and governments change them in budgets. The UK's standard VAT rate is 20%, for example, while many countries use reduced rates for food or medicine. Always use the current official rate for your country and product — the calculator does the arithmetic for whatever rate you enter.
Invoices
On a business invoice the tax is normally shown separately from the net amount. If you are registered for sales tax you usually need both figures, so keep them rather than only the total.
Rounding
Round the tax to two decimal places on each line, then add the lines up; rounding only the total can leave a small difference against your accounting software.
For margins on taxed prices, remove the tax here first and then use the Profit Margin Calculator.
Adding tax
Price including tax = price before tax × (1 + rate ÷ 100). At an 18% rate, 1,000 becomes 1,000 × 1.18 = 1,180, of which 180 is tax.
Removing tax — the common mistake
To find the price before tax from 1,180, divide by 1.18 to get 1,000. Taking 18% off instead (1,180 × 0.82) gives 967.60, which is wrong, because the 18% was calculated on the smaller, pre-tax amount. This mistake is easy to make on invoices and receipts.
Which rate?
Rates differ by country and sometimes by product, and governments change them in budgets. The UK's standard VAT rate is 20%, for example, while many countries use reduced rates for food or medicine. Always use the current official rate for your country and product — the calculator does the arithmetic for whatever rate you enter.
Invoices
On a business invoice the tax is normally shown separately from the net amount. If you are registered for sales tax you usually need both figures, so keep them rather than only the total.
Rounding
Round the tax to two decimal places on each line, then add the lines up; rounding only the total can leave a small difference against your accounting software.
For margins on taxed prices, remove the tax here first and then use the Profit Margin Calculator.
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