Construction Accounting: Job Costing Basics

You can have a busy schedule and a full crew and still wonder where the money went. Job costing answers that question by tracking every dollar you earn and spend on each project, so you can see which jobs are profitable and which ones are quietly costing you.

What Is Job Costing?

Job costing means assigning revenue and costs to a specific job instead of lumping everything together. Rather than one company-wide profit number, you see results job by job.

The Four Main Cost Categories

Labor: wages, payroll taxes, and benefits for the hours your crew spends on the job.

Materials: lumber, wire, pipe, concrete, and supplies bought for that project.

Subcontractors: payments to the trades you hire to complete parts of the work.

Equipment and other direct costs: rentals, permits, dumpsters, and fuel tied to the job.

Don’t Forget Overhead

Office rent, insurance, trucks, phones, and software don’t belong to one job, but every job must help pay for them. Allocating a share of overhead to each project shows your true profit, not just the gross margin.

Compare Estimate vs. Actual

Job costing is most powerful when you compare what you estimated to what you actually spent. If labor ran 20% over budget, you know to adjust your next bid or look at crew productivity.

Common Mistakes Contractors Make

Coding costs to the wrong job or to no job at all, waiting until a project ends to review numbers, ignoring change orders, and leaving overhead out of the picture. Each of these hides the real story of your profits.

How to Get Started

Set up jobs (or projects) in QuickBooks Online or Xero, use consistent cost codes, record time and receipts to the right job every week, and review a job profitability report at least monthly.

Know Your Numbers, Job by Job

At Horizon Business Solutions, we help contractors set up job costing, keep it accurate, and turn the reports into better bids and stronger margins. If you’re ready to see which jobs truly pay, we’re here to help.