Free calculator

GST Calculator

Free Australian GST calculator: multiply by 1.1 to add 10% GST, or divide by 11 to find the GST inside a GST inclusive price.

Last reviewed: October 2026

Amount

Total $1,100.00 including $100.00 GST

What does this amount represent?

Add GST Amount excludes GST Remove GST (reverse GST) Amount includes GST

GST rate

The GST rate in Australia is 10%. Change it only if you need to.

GST added

Base (ex GST): $1,000.00
GST (%): $100.00
Total (inc GST): $1,100.00

Next step

Invoice Generator Build a tax invoice or plain invoice and save it as a PDF
Equipment and Vehicle Finance Calculator Estimate repayments on a GST-inclusive equipment or vehicle price
Income Tax Calculator Estimate income tax and take-home pay on a wage you pay yourself
Business Loan Repayment Calculator Work out repayments and total interest on a set loan amount

How to calculate GST in Australia

To calculate GST in Australia, multiply a GST-exclusive price by 0.1 to get the GST, or by 1.1 to get the GST-inclusive total. To find the GST inside a GST-inclusive price, divide it by 11. For example, $500 plus GST is $550, and $550 including GST contains $50 of GST.

Worked examples

$1,000 plus GST: $1,100.00 (GST $100.00).
$99.99 plus GST: $109.99 (GST $9.999 rounds to $10.00).
$82.50 including GST: $75.00 plus $7.50 GST.
$99.99 including GST: $90.90 plus $9.09 GST.

The tables below round GST to the nearest cent, half a cent up, so every row adds up.

Is GST 10% or 11%?

GST in Australia is 10%, not 11%. The 11 comes from the reverse calculation: a GST-inclusive price is 11 equal parts, 10 parts base and 1 part GST, so dividing the inclusive price by 11 gives the GST. Adding GST uses 10%: multiply by 1.1.

Common amounts plus and minus GST

Both tables list the same 22 amounts: Table A adds 10% GST, Table B reverses it out. For any other amount, use the calculator above.

Common amounts plus GST (10%)

Each row adds 10% GST to a GST-exclusive amount (amount plus GST).

Adding 10% GST to common amounts: Australian GST, amount plus GST
Amount excluding GST	GST (10%)	Total including GST
$10.00	$1.00	$11.00
$20.00	$2.00	$22.00
$50.00	$5.00	$55.00
$100.00	$10.00	$110.00
$150.00	$15.00	$165.00
$200.00	$20.00	$220.00
$250.00	$25.00	$275.00
$300.00	$30.00	$330.00
$400.00	$40.00	$440.00
$500.00	$50.00	$550.00
$750.00	$75.00	$825.00
$1,000.00	$100.00	$1,100.00
$1,500.00	$150.00	$1,650.00
$2,000.00	$200.00	$2,200.00
$2,500.00	$250.00	$2,750.00
$5,000.00	$500.00	$5,500.00
$10,000.00	$1,000.00	$11,000.00
$15,000.00	$1,500.00	$16,500.00
$20,000.00	$2,000.00	$22,000.00
$25,000.00	$2,500.00	$27,500.00
$50,000.00	$5,000.00	$55,000.00
$100,000.00	$10,000.00	$110,000.00

Common amounts including GST, and minus GST (divide by 11)

Each row reverses 10% GST out of a GST-inclusive total (amount including GST, or amount minus GST).

Removing 10% GST from common GST-inclusive amounts: Australian GST, amount including GST and amount minus GST
Amount including GST	GST included	Amount excluding GST
$10.00	$0.91	$9.09
$20.00	$1.82	$18.18
$50.00	$4.55	$45.45
$100.00	$9.09	$90.91
$150.00	$13.64	$136.36
$200.00	$18.18	$181.82
$250.00	$22.73	$227.27
$300.00	$27.27	$272.73
$400.00	$36.36	$363.64
$500.00	$45.45	$454.55
$750.00	$68.18	$681.82
$1,000.00	$90.91	$909.09
$1,500.00	$136.36	$1,363.64
$2,000.00	$181.82	$1,818.18
$2,500.00	$227.27	$2,272.73
$5,000.00	$454.55	$4,545.45
$10,000.00	$909.09	$9,090.91
$15,000.00	$1,363.64	$13,636.36
$20,000.00	$1,818.18	$18,181.82
$25,000.00	$2,272.73	$22,727.27
$50,000.00	$4,545.45	$45,454.55
$100,000.00	$9,090.91	$90,909.09

How much GST do I pay on $1,000?

$1,000 plus GST is $1,100.00: the GST is $100.00. If $1,000 is the GST-inclusive price, it contains $90.91 of GST and the GST-exclusive amount is $909.09. The calculator above and the two tables use the same arithmetic.

GST and income tax are separate. If you are working out what to pay yourself, the income tax calculator estimates the income tax, Medicare levy and take-home pay on a taxable income.

Reverse GST: how to remove GST from a GST-inclusive price

To reverse GST, divide the GST-inclusive price by 1.1 to get the GST-exclusive amount, then subtract to find the GST, or divide the inclusive price by 11 to get the GST directly. A $1,100 total reverses to $1,000 plus $100 GST. A $99.99 total reverses to $90.90 plus $9.09 GST. Select "Remove GST (reverse GST)" above to do this automatically.

Dividing by 1.1 and dividing by 11 agree because 1.1 is eleven tenths. Table B above reverses GST for common amounts.

How GST works in Australia

GST is a 10% tax on most goods and services sold or consumed in Australia. That rate has applied since 1 July 2000 under the A New Tax System (Goods and Services Tax) Act 1999. Registered businesses include GST in their prices and can generally claim credits on business purchases.

One rate in every state and territory

GST is a federal tax, so an Australian GST calculator gives the same answer in every state and territory. The rate is 10% in NSW, Victoria, Queensland, WA, SA, Tasmania, the ACT and the NT, and there is no state GST. A GST calculator for NSW, Victoria or any other state is the same calculator: the maths is identical.

Who has to register

A business must register for GST once its GST turnover reaches $75,000 (as at October 2026, per the ATO and the GST Regulations 2019). The threshold is $150,000 for not-for-profit organisations.

Taxable, GST-free and input-taxed

Some sales are GST-free: the ATO lists most basic food, some education courses, some medical, health and care services, and exports. Input-taxed sales, most commonly financial supplies such as lending money and residential rent, carry no GST, and the seller cannot claim GST on related purchases.

BAS reporting cycles

Most businesses report GST quarterly on a business activity statement (BAS). Monthly reporting is compulsory from $20 million of GST turnover and optional below it; some voluntarily registered businesses report annually (ATO, as at October 2026).

The ATO's quarterly BAS due dates are 28 October, 28 February, 28 April and 28 July, or the next business day when that date is a weekend or public holiday. Online lodgers may be eligible for an extra two weeks on a quarterly BAS.

Tax invoices

Per the ATO, for sales over $82.50 including GST a supplier must give a tax invoice within 28 days of a request. Buyers need one to claim GST credits above that amount.

Financing a GST-inclusive purchase

Equipment quotes usually show the GST-inclusive price. A machine at $66,000 inc. GST is $60,000 plus $6,000 GST. A GST-registered business can generally claim that $6,000 as an input tax credit on its next BAS, while the finance can be written over the full $66,000. Timing depends on your accounting basis, so check with your accountant: general information, not tax advice. To see indicative repayments on an asset like this, try the asset finance calculator, or read how equipment finance works.

BAS or GST debt you cannot pay this quarter

If the BAS is lodged but the GST owing cannot be paid in full, the two usual routes are an ATO payment plan or paying the debt out with a business loan. Since 1 July 2025, ATO general interest charge (GIC) is no longer tax deductible, which changes that comparison; confirm your own position with your accountant. Our article on ATO payment plans versus paying it out works through a $48,000 example with the 2026 numbers. Lodge on time either way: late lodgment is a separate problem. For the finance side, see business loans.

GST calculator FAQs

How do I calculate the GST in a price?

To find the GST inside a GST-inclusive price, divide the total by 11. That works because a GST-inclusive price is 11 equal parts: 10 parts base price and 1 part GST. So a $1,100 invoice includes $100 of GST ($1,100 divided by 11). To add GST instead, multiply the GST-exclusive amount by 1.1.

Is GST always 10%?

The GST rate in Australia is 10%, and it has not changed since GST began in 2000. Not everything carries it, though: some items are GST-free, such as most basic food, and some are input-taxed. If you are unsure how GST applies to what you sell, check with the ATO or your accountant.

What does reverse GST mean?

Reverse GST means working backwards from a GST-inclusive price to find the GST-exclusive amount and the GST inside it. Divide the inclusive price by 1.1 for the base amount, or by 11 for the GST. For example, $550 including GST reverses to $500 plus $50 GST. Our calculator does this in "Remove GST (reverse GST)" mode.

Is GST the same in every Australian state?

Yes. GST is a federal tax set by the Australian Government, so the rate is 10% in New South Wales, Victoria, Queensland, Western Australia, South Australia, Tasmania, the ACT and the Northern Territory. There is no state or territory GST. A GST calculator for NSW, VIC or any other state uses exactly the same maths.

Who has to register for GST in Australia?

A business must register for GST once its GST turnover reaches $75,000 a year, or $150,000 for a non-profit organisation (as at October 2026). Taxi and ride-sourcing drivers must register regardless of turnover. Below the threshold, registration is optional. The ATO sets these rules and they can change, so check your own position with the ATO or your accountant.

What is GST-free in Australia?

GST-free sales carry no GST, although the seller can still claim GST credits on related purchases. The main GST-free categories are most basic food, some education courses, some medical and health services, some childcare, and exports. Input-taxed sales, such as residential rent and financial supplies like lending money, are different again. Check the ATO's current lists for your own products.

How do I show GST on a tax invoice?

The ATO requires a tax invoice to show it is a tax invoice, the seller's identity and ABN, the date, items with quantity and price, which items are taxable, and the GST. Where GST is exactly one eleventh of the price, stating that the total includes GST is enough. Sales of $1,000 or more need the buyer's identity or ABN.

Can I finance a GST-inclusive equipment price?

Equipment finance is commonly written over the GST-inclusive price, so a $66,000 machine including GST can be financed at the full $66,000 rather than the $60,000 base, if the lender agrees. Whether and when your business claims the $6,000 GST through its BAS depends on registration and accounting basis: ask your accountant. 121 Brokers is a broker, not a lender.

This calculator and guide are published by the 121 Brokers team, a business finance brokerage based in Byron Bay NSW. The figures on this page are checked against the ATO pages and legislation listed below; the review date is shown at the top of the page. General information only, not tax advice.

Sources

ATO, How GST works (opens in a new tab) (QC22411, updated 14 September 2026)
ATO, Registering for GST (opens in a new tab) (QC22412, updated 14 September 2026)
ATO, GST-free sales (opens in a new tab) (QC22422, updated 14 September 2026)
ATO, Input-taxed sales (opens in a new tab) (QC22425, updated 14 September 2026)
ATO, Tax invoices (opens in a new tab) (QC22438, updated 18 September 2026)
ATO, Due dates for lodging and paying your BAS (opens in a new tab) (QC33695, updated 17 September 2026)
ATO, When and how to report and pay GST (opens in a new tab) (QC39643, updated 14 September 2026)
A New Tax System (Goods and Services Tax) Act 1999 (opens in a new tab), ss 9-70, 9-75, 23-5, 23-15, 29-80 (compilation 1 November 2025)
A New Tax System (Goods and Services Tax) Regulations 2019 (opens in a new tab), regs 23-15.01, 23-15.02, 29-80.01
A New Tax System (Managing the GST Rate and Base) Act 1999 (opens in a new tab), s 11

Estimate only

This calculator gives an estimate for general information only. It is not financial advice, a quote, or an offer of finance. Actual rates, fees and repayments are set by the lender and subject to approval and your circumstances.

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