What is job costing for contractors?

Job costing is tracking the actual cost of each individual job — materials, labour, and direct costs — and comparing it to what you charged, so you know the real profit on that job. Unlike a monthly profit-and-loss, it tells you which specific job types and clients make money and which quietly lose it.

How do I do simple job costing?

Capture three numbers per completed job: revenue invoiced, actual materials spent from real receipts, and actual hours worked at a fully-loaded labour rate. Gross profit is revenue minus those two costs. Do it per job rather than in aggregate, and do it the day the job finishes before the details fade.

Why is job costing important for small contractors?

Because being busy is not the same as being profitable. Aggregate revenue hides which work actually pays. Job costing reveals that some job types or clients run at a healthy margin while others barely break even, letting you reprice or drop the unprofitable work instead of scaling it.

Job Costing for Contractors

What job costing actually is

Job costing means knowing, for each job you complete, whether you made money on it and how much. Not your business overall — that one job.

Most contractors only ever see the aggregate: total revenue at the end of the month, money in the bank, a profit-and-loss statement from the accountant in spring. That tells you the business made or lost money. It does not tell you that your panel-upgrade jobs run at 45% margin while your service calls for one particular builder run at 8%. Aggregate numbers hide exactly the information you need to price better.

Job costing closes that gap. It is not bookkeeping and it is not for the tax return — it is operational intelligence that tells you which work to take more of and which to reprice or drop.

The three-number system

You do not need software with a hundred fields. After every completed, paid job, capture three numbers:

Revenue — what you actually invoiced and collected for the job.
Actual materials — real receipts for that job, not your quote estimate. Include the extra supplier run you did not plan for.
Actual labour — real hours worked multiplied by a fully-loaded labour rate (wage plus payroll taxes, insurance, and vehicle, not just the hourly wage).

Gross profit is revenue minus materials minus labour. Gross margin is that profit divided by revenue. That is the whole calculation. The discipline is not the math — it is capturing the numbers before the details fade, ideally the day the job is done.

The most common mistake is using a labour rate that is just the wage. If you pay a tech $30/hour but the truck, insurance, and downtime make the real cost $45/hour, costing at $30 makes every job look more profitable than it is. Get the fully-loaded rate right and the rest follows — see How to Calculate Your Labor Rate.

Making it a habit, not a chore

Job costing fails for one reason: it is too much work, so it does not get done. A spreadsheet that requires fifteen minutes of data entry per job will be abandoned by the third week of a busy month.

The version that survives is fast. Log actual hours and materials in under a minute while you are still thinking about the job. Don't itemise — a single materials total and an hours figure are enough to see the pattern. Run it on every job for two months and the picture becomes undeniable: certain job types and certain clients consistently underperform, and now you can do something about it before you quote the next one.

This is exactly the loop Fieldpaid automates. You log actual hours and materials in 60 seconds after the job; when the invoice clears, it shows real margin against your quoted margin automatically — per job, no spreadsheet. Run a single job by hand first with the job profit calculator to see the format.

Job Costing for Contractors: A Simple System That Actually Gets Used