VAT / Sales Tax Calculator
Enter a price and a tax rate to add tax onto a net price, or remove tax from a gross price to find the original net amount — works for VAT, GST, or any percentage-based sales tax.
All calculations happen on your device — no financial figures are sent to a server.
A customizable general tax rate — not tax or legal advice specific to any country.
What this tool does
Adds tax to a net amount, or extracts the tax from a gross amount — two arithmetically different operations — at a rate you set.
When to use it
- Issuing an invoice and needing the tax-inclusive total.
- Having a gross amount and needing to know the tax within it.
- Checking the tax on an invoice you received.
- Working out a net price for product pricing.
How to use it
- Choose the "Operation type": "Add tax to a net amount" or "Extract tax from a gross amount".
- Enter the amount and the "Tax rate %".
- Read the net amount, the tax amount and the gross amount.
A practical example
Input
A gross amount of 115 at a 15% rate, in extract mode.
Output
A net of 100 and tax of 15 — not 17.25, which is what multiplying 115 by 15% would give.
This is the commonest error in tax arithmetic: extracting tax from a gross amount is not multiplying by the rate, because the rate was applied to the net figure, not the gross one.
Limitations
- The rate is a customisable general one and is not tax or legal advice specific to any country.
- Tax systems differ in rates, exemptions and rounding; check with the relevant authority where you are.
- It does not handle multi-tier taxes or partial exemptions.
Privacy and processing
The amounts and the rate are computed locally and no invoice figures leave your device.
Technical notes
- Extraction divides the gross by one plus the rate, which is what makes it different from a direct multiplication.