Australian Business Number (ABN)
An ABN is an 11-digit number that identifies your business to the government and community. You need one if you're running a business, freelancing, or contracting. Apply free at abr.gov.au — approval is usually instant for straightforward applications. Without an ABN, clients must withhold 47% of your payments for tax. An ABN is not the same as a business name — you may need to register a business name separately through ASIC ($39 for 1 year or $92 for 3 years).
GST Registration
You must register for GST if your business turnover is $75,000 or more per year ($150,000 for non-profits). Once registered, you charge 10% GST on your sales and can claim GST credits on business purchases. GST is reported through Business Activity Statements (BAS) — quarterly for most small businesses or monthly for larger ones. You keep the difference between GST collected and GST paid on expenses. If your expenses are high, you may even get a GST refund.
BAS Lodgement
Quarterly BAS is due 28 days after each quarter ends (28 Oct, 28 Feb, 28 Apr, 28 Jul). Late lodgement attracts penalties. BAS reports your GST collected, GST paid, PAYG instalments, and PAYG withholding (if you have employees). Use accounting software (Xero, MYOB) to automate BAS preparation — it pulls directly from your categorised transactions. Many accountants charge $200-500 per BAS lodgement.
Common Mistakes
- Not registering for GST when required (penalties apply)
- Claiming GST credits on non-business expenses
- Mixing personal and business finances
- Late BAS lodgement (automatic penalties from $313)
- Not issuing tax invoices for sales over $82.50 (inc GST)