GST Calculator

About this calculator

GST (Goods and Services Tax) is a consumption tax added to the price of most goods and services. This calculator works out the GST on any amount in seconds: enter the amount, pick the rate that applies to you, and choose whether the amount already includes GST or not. It works in any currency — just type the numbers in your own currency, because the maths is the same everywhere.

How to use it

1. Enter the amount. The price before GST, or the total price including GST — depending on the mode you pick.
2. Pick the GST rate. Choose a common rate (5%, 12%, 18% or 28%) or select “Custom rate” and type any rate you need.
3. Choose the calculation type. “Add GST” if your amount excludes GST; “Remove GST” if your amount already includes it.
4. Press Calculate. You get the GST amount and the before/after totals instantly. Nothing is uploaded — it all runs in your browser.

The GST formulas

Adding GST: GST amount = Amount × Rate ÷ 100, and Total = Amount + GST amount. Example: 10,000 at 18% gives GST of 1,800 and a total of 11,800.

Removing GST: Base amount = Total ÷ (1 + Rate ÷ 100), and GST amount = Total − Base amount. Example: 11,800 including 18% GST gives a base amount of 10,000 and GST of 1,800.

Frequently asked questions

What is GST?

GST is a tax on the sale of goods and services, paid by the buyer and collected by the seller for the government. It replaced a patchwork of older indirect taxes in the countries that use it, so the same rate applies across the country instead of changing at every border.

Which GST rate should I use?

It depends on your country and the item. For example, India’s GST system uses 5%, 12%, 18% and 28% slabs for different categories, while Pakistan’s standard sales tax rate is 18%. Always confirm the rate that applies to your item and country, because rates change and some items are exempt or zero-rated — and if your rate is not listed, use the custom rate box.

Does this calculator work in my currency?

Yes. The calculator only does the percentage maths, so it works with rupees, dollars, pounds or any other currency — the numbers you type in are the numbers you get out.

What is the difference between adding and removing GST?

“Add GST” starts from a price without tax and adds the tax on top — that is what a shop does when it prints a bill. “Remove GST” starts from a tax-inclusive price and works backwards to the pre-tax price — that is what you need when a quoted price already includes tax and you want to know the tax part.

Is the GST Calculator free?

Yes — like every tool on ToolFoxHub, it is free to use with no sign-up. The page is supported by ads, and the optional sponsored link in the box above helps keep it free.

Related tools

Percentage Calculator — any percentage of any number, plus percentage change. Discount Calculator — sale prices after a discount. Tip Calculator — split a bill and work out the tip.