Job Costing

Job costing is a method of cost accounting that assigns every expense incurred on a specific job or project directly to that job. Rather than pooling costs across the business as a whole, job costing gives each piece of work its own running total - labor hours, materials purchased, subcontractor costs, equipment hire, and any other direct expenses. When the job is complete, the total actual cost is compared against the original estimate or quote to determine whether the job was profitable.

This approach is particularly valuable for project-based businesses where each job is unique. A construction contractor, an AV integrator, or a promotional merchandise distributor handling a large branded campaign will each incur different costs on every job. Job costing gives them the data to know, with confidence, which types of work generate healthy margins and which are quietly losing money.

What Job Costing Tracks

Effective job costing captures costs across three main categories. Direct materials include everything purchased specifically for the job: raw materials, components, blank goods, or equipment. Direct labor covers the time spent by employees or subcontractors on that job, valued at their cost rate. Overhead allocation assigns a proportional share of fixed business costs - premises, insurance, management time - to each job based on an agreed method, such as a percentage of labor cost or a flat rate per hour worked.

Many small businesses track direct materials reasonably well but undercount labor and rarely allocate overhead at all. This produces a misleading picture of job profitability. A job that appears to break even on materials and subcontractor costs may actually be running at a loss once unbilled labor time and overhead are factored in.

Why Job Costing Accuracy Matters

The gap between estimated cost and actual cost is where margin is made or lost. A business that quotes based on gut feel or historical averages but never checks actuals against estimates has no way to know whether its pricing is sustainable. Job costing closes this loop. When actual costs are captured consistently, pricing can be refined over time based on real data rather than guesswork.

For businesses quoting regularly - handling 20 or 30 jobs a month - even small costing errors compound quickly. A $150 undercount on labor per job, across 30 jobs a month, adds up to $4,500 of unrecovered cost before the business notices anything has gone wrong.

Zigaflow's jobs and works orders features (/jobs and /works-orders) link purchase orders, labor records, and supplier costs directly to a job, so actual vs. estimated cost is visible in real time throughout the project lifecycle.