A plain-English walkthrough: what job costing is, the formula, how to actually track it on a busy crew, the mistakes that quietly eat your margin, and how to see profit per job in real time.
In one paragraph: Job costing means tracking every cost tied to a specific job — labor, materials, subs, equipment, mileage — and comparing that total to what you charged, so you know the real profit on that job. The formula is Job profit = Price − Total job cost. The trick isn't the math; it's capturing costs as they happen so you can catch a losing job while you can still fix it, not months later.
Job costing is looking at each job on its own — not the whole business lumped together — and adding up what that one job cost you against what you charged for it. It answers the question every contractor should be able to answer but often can't: "Did this specific job actually make money?"
Business-wide numbers hide the truth. You can have a good month overall while two jobs quietly lost money and the rest carried them. Job costing surfaces the losers so you stop repeating them.
It's simple arithmetic:
Job profit = Price charged − (Labor + Materials + Subcontractors + Equipment + Other)
Margin % = Job profit ÷ Price charged × 100
The formula is easy. Capturing the inputs on a busy job is where most contractors fall down. The rule: capture costs the moment they happen, because nobody reconstructs a job accurately from memory a month later.
Log crew hours every day, tied to the job. A clock-in app beats a paper timecard — the hours are already attributed and can't get "rounded up" on Friday.
Every receipt goes to the job it's for. Snapping it on the spot means it never becomes a mystery charge in the pile on your dash.
Record sub invoices, mileage, and fees against the job when they occur, not at month-end.
The whole payoff of job costing is timing: a number you see during the job is a steering wheel; a number you see after is an autopsy. That's the gap a tool like JobTally closes — crew hours come in by GPS clock-in, materials by receipt scan, and each job shows projected profit live. You watch margin the way you'd watch a fuel gauge, and you act before you run dry.
7 days free, no card. Set up your first job in about five minutes and watch its margin live.
Then $150/mo or $1,200/yr. Unlimited crew, everything included.
Tracking all costs tied to a specific job — labor, materials, subs, equipment, mileage — and comparing them to what you charged, to see that job's real profit.
Job profit = Price − (Labor + Materials + Subs + Equipment + Other). Margin % = profit ÷ price × 100.
Capture costs as they happen: daily crew hours (ideally a clock-in app), every material receipt tied to the job, and subs/mileage recorded right away. JobTally automates this and shows projected profit live.
Costing the job only after it's done or at tax time — too late to fix anything. Track live, per job.