Ask any service business owner or agency founder how much revenue they did last month, and they'll give you a number. Ask them which specific jobs made money and which ones lost money, and most can't answer with confidence.

That's the job costing gap — and it's one of the biggest profit leaks in service businesses.

Take a typical HVAC install — you quoted $14,500 for a system changeout. But did you account for the extra trip to the supply house, the two hours of warranty callback, and the helper you pulled from another job? Or a plumber running a whole-house remodel — the bid looked great on paper, but scope creep on the rough-in ate the margin. Without job-level cost tracking, these profit leaks are invisible until tax time.

What Is Job Costing?

Job costing means tracking the actual costs (materials, labor, subcontractors, equipment, overhead) against each individual job, then comparing those actuals to what you estimated when you quoted the work. The difference between estimated and actual cost is your variance — and it tells you whether your pricing is working or whether you're giving away margin on every job.

Why Most Service Businesses Don't Do It

The honest answer: it's tedious. QuickBooks tracks transactions, but it doesn't automatically tie those transactions to specific jobs in a way that shows you profit per job. Most owners end up with a vague sense that "we did okay this month" without knowing which jobs drove the profit and which ones ate it.

The Real Cost of Not Knowing

Without job costing, you can't answer critical questions:

Are installations more profitable than service calls, or is it the other way around?
Is Crew A more efficient than Crew B, or do they just work on bigger jobs?
Are material costs creeping up and eating your margin, or is labor the problem?
Should you raise prices on certain services? If so, which ones and by how much?

How to Start Job Costing

1. Define Your Cost Categories

For most service businesses, costs break into four buckets: materials, direct labor (crew hours x loaded rate), subcontractors, and allocated overhead (vehicle costs, insurance, tools). You don't need to track every paperclip — just the categories that are material enough to affect your margin.

2. Track Estimated vs. Actual

When you quote a job, record your estimated costs by category. As the job progresses, record actual costs in the same categories. The variance between estimated and actual is where the insight lives.

3. Calculate Your Loaded Labor Rate

A common mistake is using the hourly wage as the labor cost. But a tech who earns $25/hour actually costs you $35-45/hour when you add payroll taxes, workers' comp, health insurance, vehicle, and tools. This is the "loaded rate" or "burden rate." Use this number for job costing or you'll systematically underestimate labor costs.

4. Review Monthly, Act Quarterly

Look at job profitability monthly. If you see a pattern — say, emergency service calls consistently losing money because you're underpricing them — adjust pricing quarterly. Don't react to one bad job, but do react to patterns across many jobs.

The Payoff

Service businesses that implement job costing typically find 10-20% of their jobs are unprofitable. That's not a failure — that's a gift. Once you know which jobs lose money, you can reprice them, improve efficiency, or stop offering them altogether. Either way, your margins go up.

Tools like Accomptant automate much of this by connecting to your accounting data and letting you see estimated vs. actual on every job — without manual spreadsheet work.

Job Costing 101: How to Know If You're Actually Making Money on Every Job