Construction profit margin: how to know what each job really earns

MORTAR · 6 min read

Contractor reviewing a profit and cost chart on a tablet

Plenty of contractors are busy all year and still end up with little to show for it. The usual reason isn't a lack of work — it's not knowing the profit margin on each job. If you can't say what a project actually earned after costs, you can't tell the good jobs from the ones quietly draining you. Here's how to get a grip on it.

Revenue, cost and margin

Three numbers tell the story of any job:

Revenue — what the client pays you.
Cost — what the job costs you to deliver.
Margin — what's left over: revenue minus cost.

Your gross margin percentage is simply margin ÷ revenue. A job that brings in RM10,000 and costs RM7,000 leaves RM3,000 — a 30% gross margin. That percentage is the number to watch from job to job.

Profit and cost calculation on a notepad with a calculator — Gross margin = (revenue − cost) ÷ revenue. Track the percentage, not just the ringgit.

What counts as cost

Margins lie when you forget costs. Be honest and count everything that the job consumed:

Materials — tiles, cement, paint, fittings, with wastage.
Labour — your workers' wages for the days on this job.
Subcontractors — anything you paid others to do.
Overhead — transport, fuel, tool wear, your own time.

Leave out labour or overhead and your "profit" is a fantasy. The painful jobs are usually the ones where the hidden costs were never counted.

Construction workers laying bricks, representing labour and material cost — Labour and materials are the big costs — count every man-day against the job.

Markup is not margin

This one catches people out. If a job costs RM7,000 and you add a 30% markup, you charge RM9,100 — but your margin is only about 23%, not 30%. Markup is added to cost; margin is measured against the selling price. Confusing the two is how contractors think they're making 30% while actually making far less.

Track it per project

A single business-wide number hides too much. The gold is in per-project margins: which kinds of jobs earn well, which clients are worth keeping, and where your estimates keep missing. When you compare what you quoted against what each job actually cost, your next quote gets sharper.

Contractor smiling while viewing a positive dashboard on a tablet — Know your margin per job and you know which work to chase.

How MORTAR helps

MORTAR keeps a running P&L for each project. As you log expenses and worker attendance against a job, it adds up your costs and sets them against the revenue you've invoiced — showing an estimated gross margin in green or red at a glance. It's an estimate to guide decisions, not formal accounting, but it answers the question that matters: is this job actually making money?

Want to see the margin on every job without a spreadsheet? Join the MORTAR early list.