GST / VAT Calculator
Calculate GST and VAT inclusive and exclusive amounts
GST / VAT Calculator works in both directions: add tax to a net price (price × (1 + rate)) to get the tax-inclusive total, or take a tax-inclusive total and work backward (total ÷ (1 + rate)) to find the original net amount and the tax within it.
This tool gives general estimates for informational purposes only and isn't financial advice. Consult a qualified financial advisor or your lender before making financial decisions.
How to use GST / VAT Calculator
- 1
Enter the amount.
- 2
Enter the tax rate as a percentage.
- 3
Choose whether the amount is tax-exclusive (add tax) or tax-inclusive (remove tax).
- 4
The base amount, tax, and total are shown instantly.
Everything you need to know about GST and VAT calculations
Inclusive vs. exclusive — the distinction that trips people up
A tax-inclusive price already has GST/VAT built into the total; a tax-exclusive price has it added on top. Getting this backwards is the single most common mistake — always check which direction you actually need before reading the result.
When you actually need this
- Pricing a product or service, deciding whether to quote inclusive or exclusive of tax.
- Reverse-calculating the tax amount from a total price that already includes it.
Rates vary — check your local requirement
GST/VAT rates and rules differ significantly by country and sometimes by product category — this calculator handles the math once you know your applicable rate, not the rate itself.
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Frequently Asked Questions
Why can't I just subtract the tax rate from a tax-inclusive total?
Because the tax was calculated on the smaller net amount, not the larger total — subtracting a straight percentage of the total always gives the wrong base. Dividing by (1 + rate) is the correct way to reverse it. See our full guide to adding and removing VAT or GST for worked examples of exactly this mistake.
What's the difference between "exclusive" and "inclusive" mode?
Exclusive means your entered amount doesn't yet include tax, and the tool adds it. Inclusive means your amount already includes tax, and the tool extracts the tax and base amount from within it.
Does this work for any tax rate, not just one country's?
Yes — enter whatever rate applies to you (5%, 15%, 20%, or any other), since the calculation is pure math and isn't tied to a specific country's rate.
Does this tool send my numbers to a server?
Yes — your figures are sent to our servers to compute the result and the result is returned to you; we don't store the values.
Is this tax advice?
No. This is a general calculator, not tax advice — check your local tax authority's rules for your specific situation.