Finance

What is job costing in construction?

Job costing is the accounting method that assigns every project cost to the specific job and cost code it belongs to, so a contractor can compare actual cost to the estimate while the job is still running.

An office manager and contractor review invoices with a calculator and laptop in a construction office.
Review invoices, committed costs, and cash timing together before making project decisions. AI-generated illustration.

Job costing means tracking costs by project instead of only by company. Every hour of labor, every supplier invoice, every sub pay app, and every day of equipment use gets tagged to a job and a cost code within that job. The result is a running answer to the only question that matters mid-project: are we making the money we bid?

A company-level profit and loss statement can look fine while two jobs bleed and one big job covers for them. Job costing is what exposes that, ideally while there is still time to do something about it.

The pieces of a job cost system

  • Budget by cost code: the estimate, reorganized into the same codes accounting will use. Labor, material, subcontract, equipment, and other are the usual cost types under each code.
  • Actual costs: coded timecards (with labor burden applied), vendor invoices, sub billings, and internal equipment charges.
  • Committed costs: purchase orders and subcontracts already signed but not yet billed. See committed cost.
  • Change orders: approved changes added to both revenue and budget so the comparison stays fair.
  • Forecast: the project manager's cost to complete, which turns history into a projected final margin.

Job costing on a real job

Say a concrete contractor is pouring foundations and slabs on a $620,000 warehouse. The estimate carried 2,100 labor hours for forming and placing, at a burdened rate of $62, for $130,200 of labor. Six weeks in, the job cost report shows this:

Example: forming and placing labor at week six
ItemBudgetActual to datePercent
Labor hours2,1001,38066%
Labor cost$130,200$85,56066%
Quantity placed (cubic yards)1,9001,04555%

Cost is 66 percent spent, but only 55 percent of the concrete is in. If that pace holds, labor finishes near 2,510 hours, about 410 hours or roughly $25,400 over. The superintendent learns that the second-floor slab edges are taking twice the forming time the estimator assumed. The PM can now look for a fix (a different edge form, a crew change, or a change order if the drawings changed) instead of discovering the loss at closeout.

Notice that the useful number was not the cost. It was cost compared with physical progress. Job costing without quantities or percent complete only tells you how fast money is leaving.

Common mistakes

  1. Cost codes in accounting that do not match the estimate, so nothing lines up.
  2. Crews coding time to whatever code is easiest, which makes the labor data useless.
  3. Entering invoices weeks late, so the report is always a month behind the field.
  4. Charging raw wages instead of burdened labor, which understates every job.
  5. Leaving out indirect costs that belong to the job, like job-site trailers or small tools, so jobs look better than they are.
  6. Reviewing job costs only at month end instead of weekly.

How job costing feeds the rest of the business

Job cost data is what the WIP report is built from, which in turn drives revenue recognition under the percentage of completion method, overbilling and underbilling, and the numbers a surety looks at for bonding. It also feeds the next estimate: real production rates from finished jobs are the best estimating database a company has.

Smart Business Automator pulls coded labor, invoices, and sub billings onto each project so budget, actual, committed, and forecast sit on one screen. See job costing and WIP automation, and for setup steps read how to set up job costing for a construction company.

Frequently asked questions

What percentage should labor cost on a construction project?

A universal labor percentage would be misleading. Trade, project scope, subcontracting and the denominator all matter. Compare fully burdened labor against the project estimate and comparable completed work, using consistent definitions.

What is the best job costing software for construction?

The right system must fit your accounting, cost codes, field time capture and purchasing workflow. Test it with one representative job and verify reconciliation, committed costs, exports and permissions before choosing.

How do you calculate job costing?

Assign labor, materials, equipment, subcontract and other applicable costs to a job and consistent cost codes. Add costs to date to a current remaining-cost forecast, then compare the projected result with the budget.

How much should I charge for construction labor?

Start with fully burdened labor cost and expected productive hours, then consider overhead, profit and contract terms. A billing rate and an employee’s wage are different numbers; validate the assumptions for your market.

How do I calculate my labor cost?

Add wages, applicable employer taxes, insurance, benefits and other employment costs for the period. Divide by the relevant productive hours when estimating an effective hourly cost, keeping assumptions consistent between jobs.

How much does a $20 an hour employee cost an employer?

More than wages alone, but there is no universal multiplier. For illustration, $800 in wages plus $240 in employer costs over 40 hours equals $26 per hour before any additional overhead allocation.

What is the formula for calculating labor cost?

For a planning rate, divide total applicable labor cost by productive hours. For a task estimate, multiply expected productive hours by that rate. Include overtime and other job-specific conditions where they apply.

How do you calculate construction costs?

Define the scope and quantities, estimate labor, materials, equipment and subcontract work, then include applicable indirect costs and documented risk allowances. Keep estimate, committed costs, actual costs and remaining forecast distinguishable.

Sources

  1. Procore: Job costing in construction
  2. U.S. Small Business Administration: Business financial management
Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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