Workshop Job Costing Calculator — Free Profit Margin Tool

Why Per-Job Costing Matters in a Workshop

Most workshop owners know their overall monthly revenue and costs, but many don't track profitability per job. The result: some jobs subsidise others, and you don't find out which jobs lost money until long after the invoice has been sent.

Per-job costing breaks down the true cost of each repair or service: parts (including small consumables that often go unrecorded on paper cards), labour at your actual hourly rate, and a share of workshop overhead — rent, utilities, insurance, and consumables that apply across all jobs.

Comparing this total cost against what you charged the customer gives your gross margin per job. A healthy workshop often targets 25-40% gross margin — a commonly cited range, though it varies significantly by trade, job type, and region. Breakdown repairs with urgent parts sourcing often have lower margins than planned services.

The calculator above gives you a quick per-job breakdown. For ongoing visibility, you need per-job tracking built into your workflow — logging parts and labour against each job as the work progresses, not retrospectively from a paper card at month-end.