GST & VAT calculator
Add tax to a price, or work out what the tax was inside a total you have already been given.
Your price
Pick a country preset or type any rate you like.
Result
The mistake almost everyone makes
Someone hands you a total of 11,800 that already includes 18% GST, and asks what the tax was. The instinct is to take 18% off. That gives 9,676, and it is wrong.
Taking 18% off the total gives 9,676 instead of 10,000, because the 18% was added to the smaller number, not the bigger one. On a large invoice that gap is real money.
Common rates
| Country | Name | Standard rate |
|---|---|---|
| India | GST | 18% (5%, 12% and 28% also apply) |
| United Kingdom | VAT | 20% |
| Australia | GST | 10% |
| United Arab Emirates | VAT | 5% |
| Singapore | GST | 9% |
| Canada | GST/HST | 5% federal, more with provincial |
Rates change and exceptions are common. Check with your own accountant before you rely on a number for filing.
CGST, SGST and IGST, briefly
In India the same total tax is described differently depending on where your client is:
- Same state as you — split into CGST and SGST, half each. 18% becomes 9% + 9%.
- Different state — one IGST line at the full 18%.
The amount your client pays is identical either way. Only the presentation on the invoice changes.
Say it in the quote
"25,000 plus GST" and "25,000 including GST" are 4,500 apart. Write which one you mean, every time. It is the cheapest dispute you will ever avoid.
Common questions
Is the tax-inclusive calculation the same for VAT and GST?
Yes. The arithmetic is identical — only the name and the rate change. Divide the total by 1 plus the rate to get back to the price before tax.
When do I split into CGST and SGST?
When you and your client are in the same Indian state. If they are in a different state, you show a single IGST line at the full rate instead.
Should I quote prices with or without tax?
To businesses, quote before tax — they claim it back, so the pre-tax figure is what it costs them. To consumers, quote the total they will actually pay. In both cases, say which.
Is this suitable for filing my returns?
It is accurate arithmetic, but it is not tax advice. Rates, exemptions and reverse-charge rules vary. Check with an accountant before filing.
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