Time & money
VAT and percent calculator
Add VAT, strip VAT, or measure a discount without a spreadsheet.
This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.
What this tool does
Add tax computes net × (1 + rate). Remove tax computes gross ÷ (1 + rate) and the implied tax. Discount is the same as add with a negative rate, or use percentage-of. Change mode reports ((new − old) / old) × 100.
How to use it
- Choose add tax, remove tax, percent of, change, or ‘what percent is X of Y’.
- Enter the amount and the rate or second number.
- Copy the JSON result, including the tax component when it applies.
Supported input
- One or two decimal numbers and a percent rate
Output
- JSON with result, and tax/net fields when they apply
Privacy
This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.
ConvertPass does not include your input in analytics, URLs, or error reports. Encoding: Decimal numbers. Limit: A few numbers (4.0 KB).
Limitations
- Rates are just numbers. ConvertPass does not look up the current VAT in a country.
- Compound tax systems with regional surcharges are not modelled.
- Tips and discounts are arithmetic, not legal advice.
Example
Remove 20% VAT from 120
{
"result": 100,
"tax": 20
}
Troubleshooting
- Removing VAT did not match my invoice
- Invoices sometimes apply tax to a discounted net or use a different rounding increment. This tool uses a single rate and IEEE arithmetic.
FAQ
Is remove-tax the same as subtracting 20%?
No. 20% of 120 is 24. Removing 20% VAT from 120 is 100. Use remove tax for inclusive prices.
Can I calculate a tip?
Yes. Use add tax with 12.5 or whatever rate you want. It is the same formula.
Does this know UK VAT is 20%?
It knows nothing about legislation. Type the rate that applies to the invoice in front of you.
What about a 0% rate?
Add and remove with 0 return the original amount. That is useful as a sanity check.
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Last reviewed 16 August 2026. Report a problem. Reports do not include your input.