A job costing template compares estimated against actual cost for every category on a job: materials, labor, subcontractors, equipment and overhead allocation. The critical columns are variance in dollars and variance as a percentage, because the pattern in those columns across many jobs is what tells you which parts of your estimating are consistently wrong.
Job costing is not bookkeeping, it is feedback for your estimating. This template puts estimated next to actual for every cost category and surfaces the variance that should change your next bid. Free PDF and spreadsheet.
Tracking all actual costs against a specific job and comparing them to the estimate, so you know the true profit on that job and can see where your estimating was inaccurate.
Update costs weekly during the job and complete a full analysis at closeout. Weekly updates let you catch an overrun while you can still do something about it; the closeout review is what improves future bids.
Small variances are normal on any job. The signal to watch is consistency: if labor runs over on most jobs of one type, that is a pricing correction rather than bad luck, and it should change your unit rates.
A free job costing template from WinkScope in PDF and CSV, no signup. It compares estimated versus actual cost across materials, burdened labor, subcontractors, equipment, permits, disposal and overhead allocation, with dollar and percentage variance columns, cause analysis, gross and net profit, profit per labor hour, and a section for corrections to apply to the next bid.