How short does a stop have to be to count as a microstop?

Short enough for the operator to clear without maintenance, typically a minute or two. OEE.com puts minor stops well under five minutes and sets the cutoff by your reason-code policy: longer stops get a reason and count as downtime.

Should I value lost units at selling price or margin?

Use contribution margin, selling price minus variable cost. Material and energy for a unit you never made are not spent, so only the margin is lost. That holds when the line is sold out.

Why does my downtime report show far fewer stops than operators see?

Short stops often go unrecorded; OEE.com notes most companies do not track minor stops accurately. Count them from the machine run signal or a stopwatch study of a full shift, not from reason-coded downtime.

Where do microstops show up in OEE?

In performance. OEE.com counts small stops with slow cycles as running below top speed, so they lower the performance factor, not availability. Stops past your reason-code cutoff are downtime and lower availability instead.

Conveyors calculator

Microstop Loss Calculator

Turn a microstop count and average stop length into lost run time, lost units and lost margin a year. You need a PLC stop log or timed shift study, the running rate and unit margin.

What this calculator does

What short, operator-cleared stops cost a line in run time, units and contribution margin, per observed shift and per year.

Formula used

Time lost (min) = microstops × average stop duration (sec) ÷ 60
Share of observed time = time lost ÷ observed minutes × 100
Units lost = time lost ÷ 60 × running line rate (units / hr)
Contribution lost = units lost × contribution margin per unit
Annual loss = time lost ÷ observed minutes × production hours per year × line rate × contribution margin

Inputs explained

Microstops Counted: Operator-cleared stops from the PLC run signal or a tally sheet.
Average Stop Duration: Mean stop length from PLC timestamps or a stopwatch study.
Observed Minutes: Minutes the stops were counted over, breaks excluded.
Running Line Rate: Counter rate while the line runs between stops.
Contribution Margin per Unit: Selling price minus variable cost, from cost accounting.
Production Hours per Year: Scheduled line hours a year from the production plan.

How to use the result

Best suited to justifying a feeder, guide rail or sensor upgrade, ranking stop reasons from a PLC log.
Leaves out the ramp back to speed and any restart scrap, so the loss is a floor. If overtime can recover the lost units, the real cost is the overtime, not the margin.

Current U.S. benchmarks

The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

How short does a stop have to be to count as a microstop? Short enough for the operator to clear without maintenance, typically a minute or two. OEE.com puts minor stops well under five minutes and sets the cutoff by your reason-code policy: longer stops get a reason and count as downtime.
Should I value lost units at selling price or margin? Use contribution margin, selling price minus variable cost. Material and energy for a unit you never made are not spent, so only the margin is lost. That holds when the line is sold out.
Why does my downtime report show far fewer stops than operators see? Short stops often go unrecorded; OEE.com notes most companies do not track minor stops accurately. Count them from the machine run signal or a stopwatch study of a full shift, not from reason-coded downtime.
Where do microstops show up in OEE? In performance. OEE.com counts small stops with slow cycles as running below top speed, so they lower the performance factor, not availability. Stops past your reason-code cutoff are downtime and lower availability instead.

Last reviewed 2026-10-01.