A trades business, electrical, plumbing, HVAC, fit-out, lives or dies on job margin, and job margin is exactly what most trades bookkeeping never shows. The work is booked, the invoices go out, the bank balance moves, and nobody can actually say which jobs made money. A busy trades business can be flat out and quietly losing money on its worst jobs, subsidised by its best, with no idea it is happening.

Published: July 2026

If your trades business cannot tell you which jobs are profitable, start with the fixed-price options in The Packs and read on. This page covers service trades with crews; if you run larger construction projects, see construction bookkeeper Sydney.

What a trades bookkeeper actually does differently

• Job costing. Every cost, materials, labour, subbies, coded to the job it belongs to, so per-job margin is a real number. This is the single most valuable thing a trades bookkeeper does and the thing generalists skip.
• Do-and-charge versus quoted work. These have different economics and different risks. A bookkeeper who separates them shows you whether your quoted work is priced right and whether your do-and-charge is actually being charged.
• TPAR for subcontractors. If you pay subbies, your Taxable Payments Annual Report is due 28 August, and the data, ABNs, gross amounts, needs capturing all year, not assembled in a panic.
• Supplier account management. Trade accounts with suppliers bleed money through unclaimed rebates, pricing errors and duplicate charges if nobody watches them.
• Crew payroll. Correct awards and allowances, and from 1 July 2026, super paid every payday under the Payday Super rules.

Worked example: the worst 20% eating the best 20%

Take a Sydney electrical business doing $3M a year with three crews. Say jobs are closed without any cost review, which is the norm. In most trades businesses, the best 20% of jobs are highly profitable, the middle 60% are fine, and the worst 20% lose money, through underquoting, scope creep, callbacks or rework. If that worst 20% represents $600,000 of turnover running at a 10% loss, that is $60,000 a year the good jobs are quietly funding. The owner sees a profitable business overall and never realises a fifth of the work is destroying value. Job costing turns that invisible subsidy into a visible number, so you can requote, refuse or fix the jobs that lose money.

(Figures are illustrative, to show how job margins hide. Yours will differ.)

The cash-flow reality of a trades business

Trades cash flow is lumpy and materials-heavy. You buy materials and pay crews up front, then wait to invoice and wait again to get paid, so the business can be profitable and still cash-poor mid-job. Progress claims on bigger jobs help, but only if they are tracked and issued on time. A trades bookkeeper who keeps job costs current and watches the gap between money spent on a job and money billed for it gives you an early warning when a job is consuming cash faster than it is recovering it. Run the business off the bank balance the day a big invoice clears and you will feel flush right before a run of material orders and a quiet fortnight. Current books make the cash cycle visible instead of a monthly surprise.

Where trades overlaps other Sydney industries

Service trades share job-costing and TPAR discipline with construction (see construction bookkeeper Sydney) and the project-margin focus of engineering firm bookkeeper Sydney. Larger trades operations shade into full construction accounting.

What good bookkeeping looks like for a trades business

For a trades business, good bookkeeping means you finally know which jobs make money. Every cost is coded to its job, so per-job margin is a number rather than a feeling. Quoted and do-and-charge work are separated, so you can see whether your pricing holds and whether all your chargeable work is actually charged. Subbie payments are captured all year, so TPAR in August is a non-event. Supplier accounts are reconciled, so rebates and errors are caught. And the monthly report shows job-level profitability and the gap between money spent and money billed. The practical result is that the worst jobs stop hiding inside the good ones. You requote the work that consistently loses money, you catch scope creep while there is still time to bill it, and you price the next quote off what the last one actually cost. A trades business that can see its job margins runs on numbers instead of gut feel, which is the difference between growing profit and just growing turnover.

What you should stop tolerating

Jobs closed with no idea of their margin, TPAR assembled from a shoebox in August, supplier accounts nobody audits, and a bookkeeper who has never asked what a job cost you. A Free Xero Roast will show you where your margin is leaking, and The Packs lay out fixed-price bookkeeping built for trades businesses with crews.

FAQ

What does a trades bookkeeper cost in Sydney?
Fixed-price bookkeeping scales with job volume, crew size and complexity. A trades business needing job costing, TPAR and crew payroll sits at a clear monthly figure rather than an unpredictable hourly bill.

Why is job costing so important for trades?
Because without it you cannot tell which jobs make money. A busy business can look profitable overall while losing on specific jobs. Coding every cost to its job turns that from a guess into a number you can act on.

Do I have to lodge a TPAR?
If you pay subcontractors in building and construction, yes. The Taxable Payments Annual Report is due 28 August and reports payments to subbies. A good bookkeeper captures the data all year rather than scrambling at the deadline.

What is the difference between do-and-charge and quoted work in the books?
They carry different risks and margins. Separating them shows whether your quoted jobs are priced correctly and whether all your do-and-charge work is actually being billed, which is a common leak.

How does Payday Super affect crew payroll?
From 1 July 2026, super must be paid every payday and reach the fund within 7 business days, rather than quarterly. For a business running crews, that is a real change your bookkeeper should have running.

Can a bookkeeper help with my supplier trade accounts?
Yes. Trade accounts can bleed money through unclaimed rebates, pricing errors and duplicate charges. A bookkeeper who reconciles them catches those rather than letting them slip through.

Can you set up job costing in my existing Xero file?
Yes. Job tracking can be built into your file so every cost is coded to the job it belongs to, usually starting with a cleanup of existing coding. After that, per-job margin becomes a standard part of your monthly reporting.

What does a Free Xero Roast involve?
The team opens your Xero file, with your permission, finds the five most important issues, and sends you a short, plain-English summary. It is a high-level review, not a financial audit, and for a trades business it quickly shows whether your job margins are real or guessed.

How do I switch to a bookkeeper who understands trades?
More easily than most owners expect, and you can do it mid-year without dropping a job. The main steps are transferring ownership of your Xero subscription to you, handing over access and records, and a short onboarding where the new bookkeeper reviews the file and sets up job costing. If the file is behind or TPAR data is scattered, a cleanup sorts it first. The cost of switching is usually recovered quickly once you can see which jobs actually make money. The bigger risk is staying with a bookkeeper who cannot cost a job, because the worst 20% of jobs keep quietly eating the profit from the best.

About Sydney Bookkeeper

Sydney Bookkeeper is the modern, fixed-price Sydney bookkeeper for businesses with staff that are tired of slow, hourly, jargon-spouting incumbents. We work with professional services firms, construction and property businesses, agencies, tech and ecommerce companies, hospitality groups, and health practices across Sydney. Monthly bookkeeping, BAS lodgement, payroll, and Xero file cleanups, all on fixed monthly pricing, no lock-in.

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This content is general information only, written for Australian small and mid-market businesses. It does not constitute tax, financial product, or legal advice and should not be relied on as such. The figures used are illustrative estimates and will differ for your business. The team uses a registered BAS Agent for all BAS and IAS lodgement services; registration particulars are available on request. For advice specific to your situation, contact the team directly or consult a registered tax agent or licensed financial adviser. Sydney Bookkeeper is not a licensed tax agent or licensed financial adviser. Information was current at the time of publication and may change without notice.

Sources

• Australian Taxation Office, Taxable payments annual report (TPAR): https://www.ato.gov.au/businesses-and-organisations/preparing-lodging-and-paying/reports-and-returns/taxable-payments-annual-report
• Australian Taxation Office, About Payday Super: https://www.ato.gov.au/businesses-and-organisations/super-for-employers/payday-super/about-payday-super