Job Costing Calculator

Job costing is working out what a single job actually costs you to deliver, rather than what you hoped it would. For installation work that means on-site labour and materials, which are easy to count, plus the survey, scheduling, paperwork and invoicing time, which usually are not counted at all. The difference between the two is where margin quietly disappears.

Take the on-site hours multiplied by your loaded hourly rate, add materials at what you actually paid, then add the admin hours the job consumes multiplied by the cost of the person doing them. The calculator above does the arithmetic, but the admin hours are the input worth being honest about, because they are the ones nobody records.

Under 10% is healthy for installation work, 10% to 20% is common, and above 20% means roughly one job in five is being spent on the office. There is no universal right answer, because a heat pump with a grant application behind it legitimately carries more admin than a socket change.

No. It gives you the cost of delivering the job, not the price you should charge. Your overheads, your target margin and what the local market will bear all sit on top. Knowing the true cost is what makes the margin a decision rather than a surprise.

Because installation jobs carry paperwork that maintenance visits do not: a survey that has to be accurate, a connection notification, certificates, and a handover pack. Each is a real block of time attached to a specific job, and each is usually done by someone whose hours are treated as overhead rather than costed to the work.

It can reduce the part that is re-typing. If the survey answers become the quote, the job sheet and the connection application without anyone entering them again, several of the hours above stop existing. It cannot reduce the parts that need judgement, and any tool claiming otherwise is overselling.