Lighthouse Bookkeeping · Practical Guide

Job Costing Basics for Service Contractors

Job costing starts with a practical question: what did this particular job bring in, and what spending belongs to it? The answer depends on consistent records and a clear definition of costs.

By Lighthouse Bookkeeping

By Lighthouse Bookkeeping · Reviewed by Bosco Tanson, Founder & Managing Director · Published October 2, 2026 · Last reviewed October 2, 2026

The Short Version

Separate direct job costs from overhead.

Collect complete records for each job.

Use a clearly labeled system for tracking.

Review results with context before drawing conclusions.

Separate Direct Costs and Overhead

Direct costs are tied to a particular job, such as materials bought for that project or a subcontractor working on it. Overhead supports the business more broadly, such as general office subscriptions or costs shared across projects.

Decide how your business identifies each type before relying on a margin report. Changing the definition from one job to the next makes comparisons less useful.

Collect Complete Job Records

Keep the customer invoice, deposits, receipts, and supplier or subcontractor documents together with a reliable job identifier. A purchase description such as “materials” does not show which project used them.

Ask the people purchasing or approving work to record the relevant job while the detail is still fresh.

Use a Clearly Labeled Example

Imagine a job with $8,000 of recorded revenue, $2,000 of materials, and $2,500 of subcontractor costs. Before other direct costs and overhead, the difference is $3,500.

That figure is not automatically the final job profit. Missing labor, disposal fees, permits, or other costs could change the result. This is a hypothetical illustration, not a performance claim.

Choose the Tracking Setup Deliberately

Your software features, subscription, and working process affect how job information is tracked. Agree on the reporting requirements before deciding the QuickBooks Online structure. A separate project report is not automatically included in basic monthly bookkeeping.

Review the Result With Context

Check whether income and costs cover the same period, whether all documents are available, and how shared costs are treated. A completed project and one still in progress should not be compared without acknowledging the difference.

Keep the Scope Clear

Lighthouse can discuss contractor bookkeeping and the project information you need. We review the current setup and agree on the work before promising a particular report. Monthly bookkeeping, historical cleanup, and additional tracking are scoped according to your records and needs.

A Simple Job Cost Example

Here is how the direct costs of one job might be compared with what the job billed, with overhead kept separate.

ItemAmount
Job revenue$12,000
Materials$3,100
Subcontractor$2,400
Direct labor$3,000
Total direct costs$8,500
Job margin before overhead$3,500 (about 29% of revenue)
Hypothetical example. The figures are invented to illustrate the idea. Overhead such as insurance and office costs is tracked separately and compared with the margin from all jobs.

Common Questions

What is job costing?

Tracking the direct costs of each job so you can compare them with what the job brought in.

What counts as overhead?

Costs that support the whole business, such as insurance, office costs and general tools, rather than one particular job.

Do I need special software?

It depends on your needs and subscription. QuickBooks Online offers ways to track by project or class, and we discuss what suits your situation.

Does Lighthouse set up job costing?

We discuss the level of tracking you need and confirm what is included in your scope.

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