Add or remove GST and VAT in seconds. This free GST / VAT calculator shows the net price, tax and gross total at any rate — and works backward from a tax-inclusive price.
Results update automatically as you type. “Remove tax” extracts GST/VAT from a tax-inclusive price.
How the GST / VAT Calculator Works
Goods and services tax (GST) and value-added tax (VAT) work the same way mathematically — a percentage added on top of a price, or already baked into one. This calculator either adds tax to a net amount or extracts it from a tax-inclusive amount, depending on which direction you need.
Formula: Add tax mode: Tax = Amount × Rate ÷ 100, Total = Amount + Tax. Remove tax mode: Subtotal = Amount ÷ (1 + Rate ÷ 100), Tax = Amount − Subtotal.
- Mode — Add tax (amount is pre-tax) or Remove tax (amount already includes tax)
- Amount — The price you enter, before or after tax depending on the selected mode
- Rate — The GST or VAT percentage that applies
- Subtotal — The price with tax excluded
- Total — The price with tax included
Example Scenarios
| Amount | Rate | Mode | Result |
|---|---|---|---|
| $100.00 | 5% | Add tax | Total: $105.00 |
| $250.00 | 7.5% | Add tax | Total: $268.75 |
| $1,000.00 | 10% | Add tax | Total: $1,100.00 |
| $500.00 | 20% | Add tax | Total: $600.00 |
| $110.00 | 10% | Remove tax | Subtotal: $100.00 |
| $215.00 | 15% | Remove tax | Subtotal: $186.96 |
GST / VAT Calculator FAQ
What's the difference between Add tax and Remove tax mode?
Add tax treats your entered amount as the pre-tax price and calculates what tax and total would be added on top. Remove tax treats your entered amount as already including tax — like a receipt total — and works backward to find the pre-tax price and the tax portion.Why isn't dividing by (1 - rate%) the right way to remove tax?
Because tax is added on top of the subtotal, not subtracted from the total, the correct reverse calculation divides by (1 + rate/100), not (1 - rate/100). Using the wrong formula understates the subtotal and overstates the tax removed.Can I use this calculator for any country's GST or VAT rate?
Yes — you enter the rate yourself, so it works for any percentage-based consumption tax, whether that's GST, VAT, or a similarly structured sales tax. The calculator doesn't assume or preload any country's specific rate.Does this handle compound taxes, like a state tax plus a national GST?
Not directly in a single pass. If two taxes apply to the same base amount, add their percentages together first. If one tax applies on top of a price that already includes the other, run the calculation twice in sequence.Why would a receipt show a different tax amount than what I calculate here?
Rounding rules vary — some jurisdictions round tax per line item, others round only the final total, and some use different rounding methods entirely. Small cent-level differences between this calculator and a real receipt are usually just rounding, not an error.Is GST the same thing as VAT?
They function almost identically — both are consumption taxes added at the point of sale — but the name used depends on the country. GST is common in places like Australia, Canada, and India, while VAT is the more common term across Europe and the UK.Related Calculators
For US-style sales tax instead of GST or VAT, try the dedicated sales tax calculator; if you're comparing a discounted price alongside tax, the discount and markdown calculator handles that side of the math; and for tax on earnings rather than purchases, see the income tax calculator.