Tax & salary

GST Calculator

Add a GST rate to a price to see the GST amount and the total payable.

  • Free
  • No sign-up
  • Updated for 2026

Your amount

$
%

Enter an amount and a GST rate to see the total.

Worked example

With these example inputs:

  • Amount before GST$1,000
  • GST rate18%

Total with GST: $1,180

  • Added amount$180
  • Base amount$1,000

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What this GST calculator does

This calculator shows your total with GST. You enter the amount before GST and the rate. The tool then adds the GST on top. So you see the GST and the full total. It also shows the tax part alone. The result appears in your chosen currency.

What GST is

GST is a goods and services tax. It is added to the price of most things. So the buyer pays it at the till. The seller passes it to the government. Many countries use a GST or VAT. This tool works out the amount.

How it is calculated

The tool takes your amount before GST. It works out the GST at your rate. It then adds that to the base. So the total is the price plus the tax. The result is your total with GST. The calculator works it out for you.

What the result tells you

The result shows your total with GST. A thousand at eighteen percent comes to one thousand one hundred eighty. A higher rate raises it. A bigger base raises it too. So it shows the full amount payable. It is a clear figure.

The amount before GST

Your amount before GST is the base price. It is the price without any tax. A bigger base lifts the total. So this number sets the base. Use the price before GST is added. It drives the entire result here. Enter your amount before GST.

The GST rate

Your GST rate is the percent charged. It is set by the tax rules where you are. A higher rate lifts the total. So this number drives the tax. Use the rate that applies to the item. Rates differ by country and good. Enter your GST rate.

The GST amount

The tool also shows the GST amount alone. It is the tax added to the base. Here it comes to one hundred eighty. So you see the tax on its own. It is the part that goes to the government. It rises with the rate.

GST inclusive versus exclusive

A price can be inclusive or exclusive of GST. Exclusive means GST is added on top. So this tool adds GST to a base price. Inclusive means GST is already in the price. To strip it out you would work backward. Check which one a price uses.

Why this matters

Knowing the total with GST avoids surprises. The shelf price may not include the tax. So the till total can be higher. It helps you budget the real cost. Businesses must charge and report it. Use it to quote a correct price.

How to use it

Enter your amount before GST first. Add the GST rate. Read the total with GST in the currency you choose. Then see the GST amount alone. Try a different rate. Compare two prices. Use it to plan a purchase.

A final tip

Use this to add GST to any price. Remember rates differ by place and item. Some goods are zero-rated or exempt. A business can often reclaim GST it pays. Always use the rate for your case. Do not mix inclusive and exclusive prices. The total is the price plus the tax.

Frequently asked questions

What are the GST slabs?

GST is charged in slabs, commonly 5%, 12%, 18% and 28%, depending on the goods or service. Enter the slab that applies to your item.

How is GST added to a price?

Multiply the price by the GST rate to get the GST, then add it to the price. For example, 18% on 1,000 adds 180, for a total of 1,180.