ToolBox FreeFINANCE TOOL
GST / VAT Calculator
Add tax to a net price or remove it from a gross price. You enter the tax rate, so it works for any country.
How to use the GST / VAT Calculator
Choose whether you are adding tax or taking it out, enter the amount and your tax rate, then press Calculate. Tax rates differ by country, region and type of goods, so the rate is left blank for you to fill in from your local tax authority or invoice.
The formulas
Adding tax: total = price × (1 + rate ÷ 100). Removing tax: price before tax = total ÷ (1 + rate ÷ 100). The tax amount is the difference. A common mistake is subtracting the rate from a tax-inclusive total; this tool avoids that by dividing instead.
Examples and uses
100.00 at 10% becomes 110.00 (tax 10.00). Removing 10% from 110.00 returns 100.00. Removing 10% from 100.00 gives 90.91, not 90.00, because the 10% applies to the pre-tax price.
Limitations and good to know
This is a general-purpose calculator and not tax advice. It rounds to two decimals, so invoices with many lines or tax calculated per item may differ by a cent or two. Always confirm rates and rounding rules with your tax authority or accountant.
Frequently asked questions
Which tax rate should I use?
The rate that applies to your country and the item. Check your tax authority’s website or your invoice.
What is the difference between GST and VAT?
Both are consumption taxes added at each stage of supply. The names and rates differ between countries.
Why does removing tax give a different number than subtracting a percentage?
The tax was calculated on the pre-tax price, so you must divide the total by one plus the rate.
Related tools
Looking for something else? Browse all free online tools on the ToolBox Free Hub homepage.