Free tool
OEE calculator
Overall equipment effectiveness (OEE) measures how much of a machine's planned production time is truly productive. It is availability × performance × quality: the share of planned time the machine runs, how fast it runs against its ideal rate, and the share of parts that are good.
OEE formula
OEEequalsAvailability × Performance × Quality
AvailabilityequalsRun time divided by Planned production time
PerformanceequalsIdeal cycle time × Total count divided by Run time
QualityequalsGood count divided by Total count
Breaks, meetings, no orders
Breakdowns, changeovers, waiting
Fastest possible time for one unit
Good and bad units
Scrapped or reworked
Pre-filled with the worked example. Replace the numbers with your own shift; results update as you type.
OEE
72.9%
486 good units in 400 minutes of planned production time.
Availability
90.0%
360 of 400 min running
Performance
90.0%
Actual speed vs ideal
Quality
90.0%
486 of 540 good
Prefer a spreadsheet? Download the Excel version: the free OEE tracking sheet works out availability, performance, quality and OEE for each of 21 shifts and charts the weekly trend.
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How to calculate it
How to calculate OEE: six numbers from one shift
Shift length and planned stops give planned production time, the time the machine was meant to run. Breaks and meetings are not losses, so they are taken out first.
Unplanned downtime is every minute the machine should have run but did not: breakdowns, changeovers, waiting for material. It sets availability.
Ideal cycle time and total count set performance: how many units the run time could have made at full speed, against how many were made.
Rejects set quality. Count anything scrapped or reworked, since a reworked part was not good the first time.
Each factor points at a different kind of loss. The six big losses sort them into equipment failures and setups (availability), minor stops and slow running (performance), and defects and startup losses (quality).
OEE calculation example
Illustrative numbers, not a benchmarkA 450-minute shift with 50 minutes of planned breaks and 40 minutes of unplanned downtime. The ideal cycle time is 36 seconds, 540 units were made and 54 were rejected.
Step 1
Planned production time = 450 − 50 = 400 min. Run time = 400 − 40 = 360 min.Step 2
Availability = 360 ÷ 400 = 90%.Step 3
Performance = (36 s × 540) ÷ (360 min × 60) = 19,440 ÷ 21,600 = 90%.Step 4
Quality = (540 − 54) ÷ 540 = 486 ÷ 540 = 90%.
A note on the 85% “world-class” figure
The 85% OEE figure often called world-class is usually attributed to Seiichi Nakajima, who set out Total Productive Maintenance in Introduction to TPM (Productivity Press, 1988). Treat it as a reference point, not a target for every process: the Wikipedia article on OEE lists situations where it does not fit. Your own line's OEE, tracked shift by shift, is the comparison that shows whether improvements are working.
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<iframe src="https://www.theleansuite.com/tools/oee-calculator/embed" title="OEE calculator by LeanSuite" width="100%" height="1000" style="border:0;max-width:1000px" loading="lazy" allow="clipboard-write"></iframe>
<p style="font:13px/1.4 sans-serif"><a href="https://www.theleansuite.com/tools/oee-calculator">OEE calculator</a> by LeanSuite</p>How LeanSuite helps
LeanSuite's KPI Dashboards track OEE, downtime and production counts live, so you can clear bottlenecks early and keep production on schedule.
See KPI DashboardsRead more
- Free template: OEE tracking sheet
- Free template: Six big losses worksheet
- Free template: Downtime reason codes template
- Overall equipment effectiveness (OEE) in the lean glossary
- Overall Equipment Effectiveness (OEE): What is it?
- Reducing machine downtime: a worked month from one downtime log
- Best OEE software: a buyer's guide to eight tools
- How to calculate OEE by hand, with a worked example
FAQ
OEE calculator: common questions
Multiply availability by performance by quality. Availability is run time divided by planned production time, performance is ideal cycle time times total count divided by run time, and quality is good count divided by total count. The same result comes from one shortcut: good count times ideal cycle time, divided by planned production time.
Planned stops are time the machine was never meant to run, such as breaks, team meetings or no orders; they are taken out before OEE is measured. Downtime is time the machine was meant to run but did not, such as breakdowns, changeovers and waiting for material; it lowers availability.
Ideal cycle time is the fastest time the machine or line can make one unit under ideal conditions, often the nameplate or design rate. Using a slower 'typical' time makes performance look better than it is, and can push it above 100%.
Performance above 100% means more units were counted than the ideal cycle time allows in the run time. The ideal cycle time is usually set too slow, or the counts or run time are wrong. Set the ideal cycle time to the fastest the equipment can run.
100% OEE means only good parts, made as fast as possible, with no stop time. The 85% figure often called world-class is usually attributed to Seiichi Nakajima's work on Total Productive Maintenance (TPM). It is a reference point rather than a target for every process; the most useful comparison is your own line's OEE over time.
No. Utilization usually compares run time with all available time, and efficiency often compares output with a target. OEE combines three losses in one number: stops (availability), slow running (performance) and defects (quality), all measured against planned production time.
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