Downtime Pareto Calculator

How this is calculated

A Pareto analysis sorts your downtime reasons from largest to smallest and adds up their shares. In most plants a small number of reasons, the "vital few," account for most of the lost hours, often close to the classic 80/20 shape.

Reading the chart

• Attack the vital few first. Improvement effort spread evenly across every reason moves slowly; the same effort focused on the top one or two bars moves the total fast.
• 80/20 is a pattern, not a law. If your bars are nearly flat, downtime is fragmented and the win is usually better categorization, not a single fix.
• Beware the "Other" bucket. If a catch-all category lands near the top, your reason codes are too coarse. Split it before acting on it.
• Hours, not counts. This ranks by lost hours. A reason with many short stops can still rank below one long weekly event; run the same analysis on event counts if chronic minor stops are your suspicion.
• Garbage in, garbage out. Manually logged downtime routinely undercounts short stops. Treat the ranking as directional until the data capture is trustworthy.

Once you know which reason to attack, size the prize with the plant's numbers: the machine downtime guide covers how to track and cut the top causes, and if breakdowns lead your list, the MTBF, MTTR and availability calculator and the preventive maintenance ROI calculator will help you build the case. For the loss framework behind the categories, see the OEE calculation guide.