SpectraResource · job costing
Make the commercial learning visible.
Compare estimate, actuals and approved variations without treating one job as a universal price rule.
Published by Spectra · no named expert reviewer is claimed · last reviewed 17 September 2026 · operational guidance, not technical, legal or safety certification.
The practical answer
Job costing is a way to ask better questions about a delivered job. It is not accounting advice, tax advice or a forecast; use your approved financial controls and advisers.
Compare
Keep the causes separate.
Group quoted revenue, estimate inputs, actual material, labour, subcontract and installation cost under one job reference. Tag an approved customer change differently from rework, an access delay or a material-yield difference.
| Measure | Relationship | Interpretation |
|---|---|---|
| Gross profit | Revenue − direct cost | Not net profit |
| Margin | Gross profit ÷ revenue | Selling-price basis |
| Markup | Gross profit ÷ direct cost | Cost basis |
Worked sample
Reconcile a fictional multi-site rollout.
Synthetic sample: MSR-031 estimated direct cost is £2,400; actual is £2,620. The £220 difference is recorded as £140 approved extra location scope and £80 additional travel, not one undifferentiated overrun. With synthetic revenue of £3,300, illustrative gross profit is £680 and illustrative margin is about 20.6%.
Act
Assign the next decision.
Ask whether the variance changes a quoting assumption, a supplier process, a survey question or a scheduling rule. Retain the evidence source so future reviewers can challenge the conclusion.
A sample, not a promise