GST calculator
Add or remove goods and services tax, and work out the net amount for a return.
GST
Estimate$100.00
Divide the GST-inclusive price by 11 — never take 10% off
- Price before GST
- $1,000.00
- Price including GST
- $1,100.00
- Net GST on your BAS
- $100.00
| GST-inclusive amount entered | $1,100.00 |
|---|---|
| GST component | $100.00 |
| Net GST payable | $100.00 |
- To remove GST, divide by 11. Taking 10% off a GST-inclusive price gives the wrong answer every time.
- Registration is compulsory once turnover reaches $75,000, or $150,000 for non-profits.
To remove 10% GST from $1,100 you divide by 11, giving $100 of GST. Taking 10% off gives $990, which is wrong by $10.
How this is calculated
How this is calculated
Removing tax is division, not subtraction
Where the rate is 10%, tax is one eleventh of the tax-inclusive price. On $1,100 that is $100. Subtracting 10% gives $990 and understates the pre-tax price by $10.
tax = inclusive ÷ (1 + 1/rate)Returns report the net position
You remit tax collected less credits on business purchases, so $5,000 collected against $22,000 of tax-inclusive purchases leaves $3,000 payable.
Registration thresholds are turnover-based
Australia requires registration at $75,000 of turnover, or $150,000 for non-profits, with some industries required to register from the first dollar.
Worked example: Removing 10% GST from an $1,100 invoice
| Amount | $1,100 |
|---|---|
| Mode | Remove GST |
| GST | $100 |
|---|---|
| Before GST | $1,000 |
Rates and registration thresholds differ by country. Pick a country above for the rules that apply to your business.
What this assumes
- A standard-rated supply.
- Not exempt or zero-rated.
- Registered on an accruals basis.
- Valid invoices held for all credits.
Where this commonly goes wrong
- Some supplies are zero-rated or exempt, and charging the standard rate on them creates a liability you must later refund.
- Exempt supplies usually block input credits entirely, which is different from zero-rated supplies where credits remain claimable.
- Credits generally require a valid tax invoice above a small threshold, and missing invoices are the most common audit adjustment.
Questions
How do I work backwards from a tax-inclusive price?
Divide by 11 where the rate is 10%. On $1,100 that gives $100 of tax and $1,000 before tax. Subtracting 10% instead gives $990, understating the pre-tax price by $10 on every invoice.
Is adding and removing tax symmetrical?
No. Adding 10% to $1,000 gives $1,100, but taking 10% off $1,100 gives $990 rather than $1,000. The correct reverse operation is division, not subtraction.
What does a return actually report?
The net position rather than the gross: tax collected on sales less credits on business purchases. $5,000 collected against $22,000 of tax-inclusive purchases leaves $3,000 payable, because those purchases carry $2,000 of recoverable credits.
When must a business register?
Australia requires registration once turnover reaches or is projected to reach $75,000, within 21 days, rising to $150,000 for non-profits. Some industries, including ride-share and taxi work, must register from the first dollar of revenue.
What is the difference between zero-rated and exempt?
Zero-rated supplies carry no tax but still allow credits on the costs of making them. Exempt or input-taxed supplies carry no tax and allow no credits at all, which makes them materially worse for the seller.
Related tools
Sources
General estimate based on published ATO rates for the the current period. Not tax advice, and it does not consider your objectives, financial situation or needs. Confirm your position with the ATO or a registered tax agent.
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