Quick start
- Type the amount, for example 1000.
- Type the tax rate, for example 18 for 18% GST or 20 for 20% VAT.
- Choose whether to add tax to the amount or remove tax from a price that already includes it.
Adding tax
Multiply the price before tax by 1 plus the rate. For 1,000 at 18%: tax = 1,000 × 0.18 = 180, and the total is 1,000 × 1.18 = 1,180.
Removing tax from an inclusive price
Divide the total by 1 plus the rate. A price of 1,180 including 18% GST is 1,180 ÷ 1.18 = 1,000 before tax, so the tax inside it is 180.
A common mistake is to take 18% off the total. 18% of 1,180 is 212.40, which would leave 967.60, and that is wrong. The tax was charged on the lower price, so you must divide, not subtract.
Common rates
| Country | Tax | Standard rates |
|---|---|---|
| India | GST | 5%, 18% and 40% slabs, with some goods at 0% |
| United Kingdom | VAT | 20% standard, 5% reduced |
| Australia | GST | 10% |
| New Zealand | GST | 15% |
| Canada | GST / HST | 5% GST, or 13–15% HST in some provinces |
Rates change from time to time and depend on the product, so check the current rate for your item with the tax authority.
CGST, SGST and IGST in India
For a sale within one state, Indian GST is split equally between the central and state government. 18% GST becomes 9% CGST plus 9% SGST. For a sale between states, the full 18% is charged as IGST. The calculator shows both.
Common questions
How do I add 18% GST to a price?
Multiply by 1.18. A price of 500 becomes 500 × 1.18 = 590, of which 90 is GST.
How do I find the price before VAT?
Divide the price including VAT by 1 plus the rate. At 20% VAT, 120 ÷ 1.2 = 100 before VAT, so the VAT is 20.
Is GST the same as VAT?
They work the same way: a tax added at each stage of sale. Different countries use different names.
Is this tax advice?
No. It shows the arithmetic. Check the correct rate and rules for your goods with your tax authority or accountant.