Free tool
OEE Calculator: See Your OEE Two Ways
Your OEE report says 82%, and the line still needs Saturday overtime to make the week. The math is usually fine. The difference sits in what the report counts as planned time and which cycle time it calls ideal. This calculator shows your OEE both ways and which choice moves it most.
Works on one machine or the bottleneck of a line. Free, and nothing you enter leaves the page.
Why use it
A good OEE number can still hide the week’s losses
OEE is three ratios multiplied together, and each one rests on a definition someone chose: what counts as planned time, which cycle time is ideal, which parts are good. Small choices add up.
Performance reads 100% or more on some shifts.
The cycle time in the report is slower than the line can run.
Caught byIdeal cycle check
OEE looks fine, but the line runs overtime to make the week.
Changeovers, PM or meetings come out of planned time.
Caught byPlanned time check
Quality is near 100%, and there’s a rework bench at the end of the line.
Reworked parts count as good.
Caught byFirst-pass quality check
Speed loss is the biggest bar every week, and nobody can say why.
Startup scrap is never logged, so its time shows up as slow running.
Caught byStartup scrap check
If any of these sound like your line, the calculator shows how many points each one is worth.
Who it’s for
Check the number before it goes on the slide
Plant managers
Before the monthly ops review, or when corporate asks for a number.
CI leads
Baselining a line before a SMED or TPM event.
Maintenance managers
When the argument starts over whether PM counts against availability.
Production managers and supervisors
When the shift’s number and the dashboard disagree.
Operations directors
Before comparing plants, run each one through the same definitions.
How it works
Three steps
Enter one week the way you report it
Scheduled time, stops, units made, good units and the cycle time your report uses. Take them straight from last week’s report.
Answer five questions on how it’s counted
What comes out of planned time, where the cycle time comes from, and how rework and startup scrap are counted. Not sure is always an option.
Take both numbers to your next ops review
You get both OEE numbers with availability, performance and quality for each, the points each definition choice is worth (on Line 3, 9.1 for the ideal cycle and 7.5 for changeovers), five checks passed or flagged, and a definitions summary. Copy it, email it or print it.
The method
Five checks on how your OEE is counted
Each check tests one definition behind the number. The examples come from Line 3, the sample line in the tool below.
Planned time
What does your report take out of planned time?
Passes whenOnly breaks and time with no orders come out of planned time.
Why it mattersOEE.com counts changeovers and PM as availability loss.
PassesBreakdowns and waiting on material count as downtime.
FailsLine 3 takes 360 minutes of changeovers out of planned time.
Ideal cycle
Which cycle time does your report call ideal?
Passes whenThe ideal is the nameplate rate or the fastest the line has run.
Why it mattersA standard or budget time inflates performance and hides speed loss.
Passes26 seconds, the fastest Line 3 has run.
FailsLine 3 uses the 30-second routing standard.
Speed over 100%
Does performance ever read over 100%?
Passes whenPerformance stays at or under 100%.
Why it mattersAbove 100% means the ideal cycle is set too slow.
PassesLine 3 reads 94.2%.
FailsA line running 27-second cycles against a 30-second ideal reads 111%.
First-pass quality
Are reworked parts counted as good?
Passes whenGood means right the first time.
Why it mattersRework is a quality loss.
PassesScrap is logged against the total.
FailsLine 3 counts 150 reworked parts as good.
Startup scrap
Are parts scrapped at startup in the total?
Passes whenParts scrapped at startup are in the total.
Why it mattersWhen they’re missing, their time shows up as slow running.
PassesLogged after every changeover.
FailsLine 3 leaves 80 startup parts out.
Try it
Check an OEE number
Open the example to see finished results, or enter one week from your own report. Nothing you enter leaves this page.
Get started
Pick a starting point
Have last week’s OEE report in front of you. Your numbers stay in this page and clear when you close it.
Common questions
What counts, and where the benchmarks come from
Choose Not sure. A stop you’re not sure about is treated as excluded, the way many reports treat it, and your results list it under Find out so you can check before the review.
Leave it out of scheduled time. The OEE.com FAQ treats it as schedule loss, which TEEP covers and OEE leaves out.
Use the main product’s cycle for now, or run the calculator once for each product and compare the gaps.
Keep reporting it, and track the standard number alongside. The gap breakdown shows which part of the rule moves the number most.
No. The OEE.com FAQ treats any factor above 100% as a sign that something is defined or measured wrong, almost always an ideal cycle set too slow, and ISO 22400-2 sets the OEE range at 0 to 100%. A line running 27-second cycles against a 30-second ideal reads 111% performance, so the calculator moves the standard column to the line’s actual average cycle.
The OEE.com FAQ counts changeover time as availability loss, because it’s production time the line loses and SMED can win back. Some plants take changeovers out of planned time, which raises the number. The calculator shows both: on Line 3, 360 minutes of changeovers are worth 7.5 points.
The OEE.com FAQ counts planned maintenance as availability loss when it uses time the line could run to meet demand. For breaks, it notes most companies leave them out, and counts them as best practice when they cost production time. The calculator leaves breaks out in both columns and counts PM as downtime in the standard column.
No. The OEE.com FAQ calls it well-accepted practice to count a part that needs rework as a reject the first time through, which makes OEE quality close to first-pass yield. Line 3 counts 150 reworked parts as good, which is worth 1.5 points.
Seiichi Nakajima’s Introduction to TPM (1984, in English in 1988) set 90% availability, 95% performance and 99% quality as world-class levels, which multiply to about 85%, as OEE.com explains. Evocon’s data puts most plants closer to 55 to 60%.
OEE compares fully productive time with planned production time. TEEP, as the OEE.com FAQ defines it, compares it with all the hours in the week, so it also counts the shifts you don’t schedule. TEEP shows how much capacity the plant has; OEE shows how well it uses the time it plans to run.
The OEE.com FAQ recommends a weighted average, weighting each machine’s OEE by its planned production time. For a line, measure OEE at the bottleneck, because the bottleneck sets the line’s output.
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