Invoicing from the ute, GST on materials, vehicle claims, and job costing — the practical bookkeeping habits that keep a trades business out of BAS-time panic.
Most tradies didn’t get into the trade to spend their evenings sorting receipts. But the businesses that run smoothest — steady cash flow, no BAS surprises, no scrambling at tax time — aren’t the ones with the least admin. They’re the ones who’ve replaced the shoebox with a handful of simple, consistent habits that take minutes rather than hours each week.
The longer the gap between finishing a job and sending the invoice, the longer it takes to get paid — and the easier it is for a job’s details to get fuzzy by the time you sit down to write it up. Mobile invoicing apps let a job be invoiced from the ute before you’ve even left the site, while the materials used and hours worked are still fresh. It also means a week’s worth of invoicing doesn’t pile up waiting for a rainy day.
A common source of BAS errors in trades businesses is materials and labour getting lumped into one general expense category, or GST being applied inconsistently across supplier invoices. Setting up a clean chart of accounts that separates materials, labour, subcontractor costs, and vehicle expenses — with GST coded correctly on each — means BAS prep is a quick review rather than a full untangling exercise every quarter.
Knowing the business made a profit for the year doesn’t tell you which jobs were actually worth taking on. Job costing — tracking materials, labour, and time against each specific job — shows which types of work are genuinely profitable and which are quietly being underquoted. This matters more as a business grows and starts taking on bigger or more varied jobs, where a flat “per hour” rate can hide a job that actually lost money once materials and travel time are factored in.
Vehicle costs are one of the largest deductions for most trades businesses, and getting the method right matters. For the 2025–26 income year, the ATO’s cents-per-kilometre rate is 88 cents, capped at 5,000 business kilometres per car — a maximum claim of $4,400. If a ute or van covers more than 5,000 business kilometres a year, which is common for tradies travelling between multiple sites, the logbook method usually delivers a larger and more accurate deduction, since it claims the actual business-use percentage of all running costs rather than a flat capped rate. A 12-week logbook can support claims for several years, provided the vehicle’s usage pattern stays representative.
Whether it’s a fuel receipt, a hardware store docket, or a subcontractor invoice, capturing it the moment it’s received — with a phone photo straight into accounting software — avoids the classic end-of-quarter scramble through a glovebox or a ute tray. It also protects deductions that would otherwise be lost to a faded receipt or a docket that never made it home.
A ten-minute weekly check — matching bank transactions against what’s recorded — keeps small errors small and catches issues like a duplicate invoice or a missed expense while it’s still an easy fix. Leaving reconciliation until BAS is due turns that same task into a multi-day job, usually done under time pressure.
GST collected on a job isn’t part of the business’s actual income — it’s money being held for the ATO. Transferring it into a separate account as invoices are paid means the BAS payment is already covered when the deadline arrives, rather than competing with wages, materials, and supplier bills.
Plenty of tradies run their own books in the early stages, and that’s entirely reasonable while the business is small and straightforward. The tipping point usually arrives when staff or subcontractors are taken on, job types diversify, or the business owner realises admin is eating into time that could be spent quoting and working. At that point, a bookkeeper who understands trades-specific job costing, GST treatment, and vehicle claims tends to save far more in time and avoided errors than the service costs.
The rate is 88 cents per kilometre, capped at 5,000 business kilometres per car — a maximum claim of $4,400. If business kilometres exceed 5,000 a year, the logbook method is generally worth considering instead.
It depends on how many business kilometres are driven each year. Under 5,000 km, the cents-per-kilometre method is simpler with no receipts required. Above that, the logbook method claims the actual business-use percentage of running costs and usually results in a larger deduction for tradies covering multiple sites.
Weekly is recommended over leaving it until BAS is due, since a short weekly check keeps errors small and catches issues like duplicate invoices or missed expenses while they’re still easy to fix.
Job costing tracks materials, labour and time against each specific job, rather than just looking at overall business profit. It shows which types of work are genuinely profitable and helps avoid underquoting jobs that look fine on the surface but lose money once every cost is accounted for.
