The job costing trap that's quietly killing your margins

Ask most owner-led businesses if they track job costs, and the answer is almost always yes. Ask them to show you the report that proves a specific job made money, and the room gets quiet. That gap, between believing you're tracking costs and actually being able to prove margin on a job, is where profit quietly disappears.

What "tracking job costs" usually means

In practice, it usually means materials get coded to a job number and labour gets a rough estimate at best. Overhead, equipment time, callbacks, and the small stuff that eats an afternoon rarely make it into the number. The job looks profitable because nobody's added up everything it actually took to deliver it.

The gap nobody catches

The real damage shows up at the portfolio level. A handful of jobs are quietly subsidizing the rest, and without job-level margin data, there's no way to tell which ones. Pricing decisions get made on gut feel instead of evidence, and the same underpriced job type keeps getting booked, again and again, because nothing in the numbers is flagging it.

How to fix it without overhauling everything

Fixing this doesn't require a new accounting system overnight. It usually comes down to three changes:

• Allocate labour to jobs using actual time, not estimates
• Build a simple overhead allocation rate so every job carries its fair share
• Review job-level margin monthly, not just at year-end

Once those three pieces are in place, the picture usually changes fast, and so does the confidence behind every quote that goes out the door.