Maintenance Backlog Calculator

How this is calculated

Backlog is the pool of identified, ready-to-schedule maintenance work that has not been done yet. Sizing it in crew-weeks tells you how many weeks it would take your current crew to clear it if no new work arrived. All figures below are your inputs.

Reading the number

A backlog of roughly 2 to 4 crew-weeks is a commonly cited healthy range: enough ready work to plan and schedule efficiently, not so much that jobs age out.

• Under about 2 weeks can mean the crew is over-resourced for the identified work, or that too much time is going to reactive breakdowns instead of planned jobs, so little backlog builds up.
• Roughly 2 to 4 weeks is the range many planners aim for. Treat it as a guide, not a hard rule.
• Over about 6 weeks usually points to being under-resourced, or to a planning bottleneck, and work is likely aging.

Caveats. This treats every open work order as ready-to-schedule and uses a single average duration, so a few large jobs can skew it. It also ignores priority, parts availability, and shutdown-only work. Ranges here are common rules of thumb, not standards; your healthy range depends on your asset mix and strategy.

To connect backlog to reliability, use the MTBF, MTTR and availability calculator, and to weigh preventive work against firefighting, use the preventive maintenance ROI calculator. For the bigger picture on planned versus reactive time, see the lean manufacturing guide.