Trade office
Job costing: turn a variance into the right next question
A paid invoice alone does not show whether a job went well. For the next quote, you need to know whether estimated hours and materials matched the work. A small post-job review reveals differences while the team still remembers the reasons.
Compare like with like
Do not compare planned installation hours with all recorded time including workshop work, travel and extras if the estimate treated them differently. Define the boundaries and track approved changes separately. For materials, use quantities actually consumed by the job: a supplier invoice may include stock for other sites. A variance is therefore not automatically an execution error.
A simple worked example
The estimate allowed 40 hours; the job took 46. That is six additional hours, or 15 percent more time. At an illustrative internal cost of €35 per hour, the extra time costs €210. This is neither a selling price nor automatically a loss. The overall result still needs materials, other costs and the agreed payment to be considered.
Choose an action rather than someone to blame
Discuss what explains the six hours: quantity, difficult access, extra work or poor preparation. Link the finding to one practical action. Perhaps the service bundle needs a different labour allowance or the site survey needs another question. Preserve the original estimate. Rewriting it to match the result removes exactly the information you wanted to learn from.
Your business checklist
- Agree scope and cost basis before comparing figures.
- Separate extra work and stock purchases correctly.
- Calculate time variance in hours and percentage.
- Record a concrete improvement for the next quote.