03/09/2026
One of the most common bookkeeping slip-ups I see is GST claimed on things that don't actually have any.
It's an easy mistake, because it isn't always obvious. Plenty of everyday business expenses are GST-free or don't include GST at all — things like bank fees, most residential rent, some government charges, ASIC fees, and a lot of overseas purchases. Claim the GST on those and your BAS is wrong, even if only by a little each time.
It goes the other way too. Sometimes GST that could be claimed gets missed — usually because there's no valid tax invoice, or the expense was coded as personal by mistake.
None of these are dramatic on their own. But they add up quietly across a quarter, and they're exactly the kind of thing that surfaces later as a correction, or an adjustment your accountant has to make at tax time.
The fix isn't complicated — it's knowing what does and doesn't carry GST, and coding it right as you go.
Are you confident everything in your books is coded to the right GST treatment, or is it a bit of a guess?