Add GST
Your price doesn't include GST yet.
- GST =
- Amount × 0.10
- Total inc GST =
- Amount × 1.10
Example: $250.00 × 0.10 = $25.00 GST, so the total is $275.00.
Australian GST at 10%
Add GST Calculator
Use this calculator when you have a price before GST and need the price including GST, for a quote, an invoice or a price list. Type the GST-exclusive amount and you'll see the 10% GST and the total straight away.
Last reviewed 8 November 2026 by Simsim.
Total including GST
$0.00
Enter an amount to see the GST.
Add GST: amount × 1.1 = price including GST.
Remove GST: price ÷ 11 = GST included.
For general information only. GSTCal is not affiliated with the Australian Taxation Office or any government agency, and does not give financial, legal or tax advice. Check how GST applies to your situation with the ATO or a registered tax agent.
The formula
How to add GST to a price
Multiply the GST-exclusive price by 0.1 to get the GST, then add it to the price. Or, in one step, multiply the price by 1.1.
For a $250 job: $250 × 0.1 = $25 GST, and $250 + $25 = $275 including GST. The same answer comes from $250 × 1.1 = $275.
When you need to add GST
If your business is registered for GST, you generally add GST to taxable sales and show it on your tax invoices. Prices advertised to consumers in Australia must include GST, so a price list for the public should show the GST-inclusive figure.
If you're not registered for GST, you can't charge it or show it on your invoices.
Rounding
GST is worked out to the cent. When the result has half a cent or more, the calculator rounds up, otherwise it rounds down. That matches the ATO's general rounding rule for working out GST on a single item. When an invoice has several items, the ATO also lets you round the GST on the invoice total, so your accounting software may differ from a line-by-line total by a cent.
Worked examples
Calculated with the same rules as the calculator above.
| Amount | GST to add | Total inc GST |
|---|---|---|
| $10.00 | $1.00 | $11.00 |
| $45.50 | $4.55 | $50.05 |
| $100.00 | $10.00 | $110.00 |
| $250.00 | $25.00 | $275.00 |
| $999.99 | $100.00 | $1,099.99 |
| $1,500.00 | $150.00 | $1,650.00 |
| $5,000.00 | $500.00 | $5,500.00 |
| $20,000.00 | $2,000.00 | $22,000.00 |
Add GST Calculator questions
What is 10% GST on $100?
GST on $100 is $10, so the price including GST is $110.
Is adding GST the same as multiplying by 1.1?
Yes. Multiplying by 1.1 adds the original amount plus 10% of it in one step. $500 × 1.1 = $550, which is $500 plus $50 GST.
Do I add GST before or after a discount?
Work out the discounted price first, then add GST to what the customer actually pays. GST is charged on the price of the sale after any discount.