GST Calculator
Add or remove 10% GST to see the price before GST, the GST amount and the total including GST. Check a single amount or calculate multiple invoice lines in bulk.
GST details
Before you enter amounts
GST is Goods and Services Tax
GST Calculation
Start with a GST-inclusive amount. We'll remove the GST.
GST Summary
Remove GST from a GST-inclusive amount.
Price excluding GST
$0
GST component: $0
- Ex GST
- $0
- GST (10%)
- $0
- Inc GST
- $0
What's next
Reviewed by Ashma Ghimire, ASA, CPA AustraliaLast reviewed 29 September 2026
How to calculate GST
To add 10% GST, multiply the price before GST by 1.1. To remove GST, divide the total by 1.1. To find only the GST in an inclusive total, divide by 11.
Add GST to a price
A GST-exclusive price does not include tax. Multiply it by 0.1 to find the GST, then add that amount to the price. For example, $1,000 before GST + $100 GST = $1,100 including GST.
Remove GST from a total
A GST-inclusive total already includes tax. Divide it by 1.1 to recover the price before GST: $110 ÷ 1.1 = $100.00. This reverse GST calculation is useful when checking a receipt or supplier invoice.
Find the GST in a total
Divide a GST-inclusive total by 11 to isolate its GST component: $110 ÷ 11 = $10 GST. Subtracting 10% from the total gives the wrong answer because GST is a percentage of the price before tax.
These formulas assume the full amount is taxable at the standard rate. They follow the methods shown by ASIC Moneysmart. Check invoice items separately if some have no GST.
GST on common amounts
Each row starts with a price excluding GST and shows the tax added at 10%.
| Excluding GST | GST (10%) | Including GST |
|---|---|---|
| $100 | $10 | $110.00 |
| $250 | $25 | $275 |
| $500 | $50 | $550 |
| $1,000 | $100 | $1,100 |
| $2,000 | $200 | $2,200 |
| $5,000 | $500 | $5,500 |
| $10,000 | $1,000 | $11,000 |
Check invoices and estimate GST for your BAS
Single amount
Choose Add GST for a quote before tax, or Remove GST for a total that already includes it. The result shows all three amounts together.
Bulk invoice lines
Enter amounts separated by commas or new lines to calculate a batch and its totals. Use amounts with the same GST treatment and direction.
GST position
Enter GST on sales and eligible GST credits on purchases to estimate the difference for your reporting period.
Under the ATO's Simpler BAS reporting, G1 means total sales, 1A is GST on sales, and 1B is GST on purchases. Claim only eligible credits at 1B. G11, where required, records non-capital purchases; it is not the GST credit amount.
A purchase must include GST and meet the ATO's GST credit requirements. Account for any private use and keep the required tax invoices and records.
A GST estimate, not a complete BAS
The helper estimates GST on sales minus eligible credits. Adjustments, PAYG withholding, instalments, other BAS items and existing ATO account balances can change the final payment or refund. Check your reporting period and due date on your BAS or in ATO Online Services.
When to register for GST
For most businesses, the registration threshold is $75,000 in GST turnover. Check both current and projected turnover over rolling twelve-month periods, rather than just financial-year income. GST turnover excludes GST and certain sales; different rules apply to some organisations. Read the ATO registration rules for the full test and exceptions.
Taxi and ride-sourcing drivers must register from their first trip regardless of turnover. Calculate GST on the full passenger fare before platform fees, then consider eligible expense credits separately.
GST is separate from income tax. Use the contractor calculator to compare contract income and take-home pay, or the tax return calculator to estimate annual income tax. Our contractor vs employee tax guide explains how employment status affects your obligations.
Frequently Asked Questions
How do I add GST to a price?
To add GST, multiply the GST-exclusive price by 1.1. The GST itself is the price multiplied by 0.1. For example, $1,000 before GST becomes $1,100 including GST, with $100 of GST added. Use this method when a quote does not yet include tax. Select Add GST above for one amount, or use bulk mode for several taxable invoice lines.
How do I remove GST from a total?
To remove GST, divide the GST-inclusive total by 1.1. For example, $110 including GST becomes $100.00 excluding GST. The difference, $10, is the GST component. Do not simply subtract 10% from an inclusive price: the tax was calculated on the smaller price before GST. Select Remove GST above to reverse the calculation and see both the original price and its GST component.
How do I calculate GST from a total?
For a total that already includes 10% GST, divide by 11 to find the GST amount. For example, $110 divided by 11 gives $10 of GST. This is different from dividing by 1.1, which gives the price excluding GST. Only use this shortcut when the whole amount is taxable at the standard rate; mixed invoices can include items with no GST. Check the GST breakdown above.
How much GST is in $1,000?
If $1,000 already includes GST, it contains approximately $90.91 of GST and $909.09 before GST. If $1,000 is the price excluding GST, add $100 of GST to reach $1,100. The same number therefore gives different answers depending on whether tax is already included. Check the wording on your quote or receipt, then choose Add GST or Remove GST in the calculator.
What is GST and does it apply to every sale?
GST is Goods and Services Tax, charged at 10% on most goods and services sold in Australia. It does not apply to every sale. GST-free sales, such as many basic foods, generally allow credits on related business purchases. Input-taxed sales, such as residential rent, generally do not. The calculator applies the standard rate to the amount you enter; check the tax treatment before including an item in a bulk calculation.
When do I need to register for GST?
For most businesses, the GST registration threshold is $75,000. Registration depends on current or projected GST turnover over rolling twelve-month periods, not simply income earned since the start of the financial year. GST turnover excludes GST and certain sales. Special rules apply to some businesses and organisations, including ride-sourcing. Check the ATO registration rules for your circumstances; this calculator converts amounts and does not assess whether you must register.
How do Uber and other ride-sourcing drivers calculate GST?
Ride-sourcing drivers must register for GST from their first trip, regardless of turnover. To find the GST in a GST-inclusive fare, divide the full fare by 11. Use the passenger fare before the platform deducts its fees, rather than the net amount paid into your bank account. Eligible GST credits on business expenses are considered separately. Enter the fare in Remove GST mode to see the GST component and the amount excluding GST.
How does the GST estimate relate to my BAS?
A Business Activity Statement (BAS) includes GST reporting. Under Simpler BAS, G1 is total sales, 1A is GST on sales, and 1B is GST on purchases, where eligible credits are claimed. G11, when required under other reporting methods, is non-capital purchases rather than GST credits. The helper subtracts eligible credits from GST on sales. It estimates the GST position only; adjustments, other BAS obligations and account balances can change the final amount payable or refunded.
Can I claim back all the GST on business purchases?
No. GST registration alone does not make every purchase eligible for a credit. The purchase must include GST and be for a creditable business purpose; private use and purchases relating to input-taxed sales generally do not qualify. You also need the required supporting records, including a tax invoice where required. Apportion mixed business and private expenses, then enter only the eligible GST credits in the BAS helper, rather than all GST paid.