A preventive maintenance cost calculation has two sides, and a site that only works one of them cannot decide anything. The cost side is the preventive hours and parts the schedule consumes. The value side is the breakdown hours, parts and lost output the schedule removes. This page works both on this site's own example figures, shows where each number comes from in the work order history, and gives the arithmetic a site repeats with its own numbers from the maintenance log worksheet.
The cost side: preventive hours and parts
Count the preventive work orders in a month and sum their hours. This site's worked example is 60 preventive jobs at 66 hours, which at a $48 loaded technician rate is $3,168 a month and $38,016 a year. Add the parts consumed by those tasks, filters, lubricants, belts and the like, which the work orders list if parts are recorded. That is what the programme costs, and it is a figure most sites know roughly and few know exactly.
The value side: breakdowns removed
Count the reactive work orders and their hours. The example is 240 work orders a month with 35% reactive, 84 breakdowns at 3.4 hours each. The same work done as a planned task takes 1.1 hours, so each breakdown carries 2.3 avoidable hours, 193.2 hours a month, $9,273.60 at the loaded rate and $111,283.20 a year. Add the parts that fail catastrophically instead of being replaced worn, and the lost output, which the site prices in its own units. A schedule that runs does not remove every breakdown, so take the share it can reasonably prevent, the repeaters with a known failure mode, and that share of the figure is the value.
Putting the two together
Value minus cost is the programme's worth, and on the example the avoidable reactive hours alone are three times the preventive cost before lost output is counted. The comparison per asset class is more useful than the site total, because it shows which classes deserve more preventive work and which are being over-maintained: a class with many preventive hours and no reactive history is a candidate for longer intervals, and one with few preventive hours and many breakdowns is a candidate for a task.
Where the numbers come from
Every figure above is a count or a sum from work orders that record the type, the asset and the hours. A CMMS reports them from its screens; the maintenance log worksheet on this site has the same columns for a team not yet on one. A site that does not record work order type and hours cannot do this calculation, and that is the first thing to fix, before the programme is judged.
Questions people ask about preventive maintenance cost calculation
What loaded rate should I use?
Wages plus on-costs plus the share of overhead that follows the technician, per hour. Your payroll or finance team has it; the example uses $48 as an illustration.
Should lost output be included?
Yes, priced in the site's own units, because on most sites it is larger than the technician hours. The technician arithmetic is the floor the programme clears before output is counted.
How often should the calculation be repeated?
Quarterly, from the same records, so that the trend shows whether the programme is earning its hours.