GIFSQ Tools · Module 18 — Manufacturing, Costing & Supply Chain · Tool 346 of 500
Find the few downtime causes that cost the most time: enter the minutes lost to each cause and the tool ranks them, showing the share of the biggest cause and of the top two — the Pareto 80/20 view of a shift.
Try sample values — fills the form with the worked example below.
–
Total downtime (min)
–
Largest cause (%)
–
Top two causes (%)
Equation: Total = sum of all causes. Largest cause (%) = largest value ÷ total × 100. Top two (%) = (largest + second largest) ÷ total × 100.
Method: Pareto analysis (Juran): rank the causes from largest to smallest and look at the cumulative share. In most plants a small number of causes accounts for most of the lost time, so fixing the top one or two pays best.
Assumptions: the minutes for each cause are measured over the same period and do not overlap; the list covers all the downtime in the period.
Limitations: a Pareto chart shows where the time went, not why — the top cause still needs a root-cause check; small frequent stops can matter more than one long stop when they repeat.
Rounding: total as a whole number of minutes; shares to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Pareto analysis (Juran): rank the causes from largest to smallest and look at the cumulative share. In most plants a small number of causes accounts for most of the lost time, so fixing the top one or two pays best.
Assumptions: the minutes for each cause are measured over the same period and do not overlap; the list covers all the downtime in the period.
Limitations: a Pareto chart shows where the time went, not why — the top cause still needs a root-cause check; small frequent stops can matter more than one long stop when they repeat.
Rounding: total as a whole number of minutes; shares to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Downtime 120, 60, 30, 15, 5 minutes: total = 230 min; largest cause = 52.17%; top two = 78.26% — fixing the top two causes removes over three-quarters of the loss.
Enter values above to see results.
If the top two causes are under 50% of the total, the downtime is spread out — look for a systemic issue instead of one fix. Tool 346 of 500 — GIFSQ
