You only put GST on invoices once your ABN has a GST registration attached. See whether yours needs one.
Two directions, two different sums
Going forward, from your price to the invoice total, is the easy one: add 10%, so an $880 job becomes $968 on the invoice. Going backward, finding the GST inside a total you already have, trips people up, because the answer isn't 10% of the total. The GST is one-eleventh of a GST-inclusive figure: in a $968 total, the GST is $88, not $96.80.
Why eleven? Because the total is 110% of your original price. The GST is 10 parts out of those 110, and 10/110 simplifies to 1/11. Every receipt, every expense claim, every BAS line uses that little fraction.
Try it against these
| Before GST | + 10% GST | Invoice total |
|---|---|---|
| $250.00 | $25.00 | $275.00 |
| $880.00 | $88.00 | $968.00 |
| $2,500.00 | $250.00 | $2,750.00 |
| $12,727.27 | $1,272.73 | $14,000.00 |
Whether the 10% belongs on your invoices at all
An ABN alone doesn't mean you charge GST. GST is a separate registration attached to the ABN (when yours needs one). Until your business is GST-registered, your invoices show no GST and the price is just the price. Once you are registered, compulsory at $75,000 turnover, and from the first trip for rideshare drivers, the 10% goes on everything taxable you sell.
Quick answers
How do I find the GST in a total price?
Divide by 11. A $2,200 GST-inclusive bill contains $200 of GST and $2,000 of actual price. Taking 10% of the total gives the wrong answer every time, because the GST was added to the smaller number, not the big one.
I just got my ABN: do I add GST to my invoices now?
Only if your ABN also has a GST registration. They're separate: the ABN identifies your business, GST is a tax status added to it. No GST registration, no GST on invoices, and no GST shown anywhere on them.
Has GST always been 10%?
Yes, 10% since it started in 2000, with no change since. What varies is whether a sale carries it at all: basic food, most health and education are GST-free, and residential rent is input-taxed.
Can I show a GST-inclusive price to customers?
For consumers you must, advertised prices need to be the total payable. For business customers it's normal to quote ex-GST and itemise the GST on the invoice.
Related: Do I need to register for GST? · Do I need an ABN? · All business calculators
No ABN yet? That comes before the GST.
Registered Tax Agent 26076969 · usually same-day · free help on 1800 546 526.