Free calculator

OEE calculator

Enter the planned production time, the downtime, the ideal cycle time and the pieces produced. The calculator returns the three OEE factors and shows which one loses the most.

In short

OEE (Overall Equipment Effectiveness) is the share of planned production time that turns into good parts at the ideal speed. It is the product of availability, performance and quality.

Planned production time

The time the machine was scheduled to run, in minutes.

Downtime

Breakdowns, changeovers and other stops, in minutes.

Ideal cycle time

Seconds per piece at the machine’s rated speed.

Total pieces

Everything produced, good or not.

Good pieces

Pieces right first time, without rework.

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OEE

69%

Availability88%

Performance83%

Quality95%

The biggest loss is performance: the machine runs, but slower than its ideal cycle. Look at short stops, reduced speed and whether the ideal cycle time is realistic; watching the machine for a full shift often shows what the counters miss.

The formula

Availability = (planned time − downtime) ÷ planned time
Performance = (ideal cycle time × total pieces) ÷ run time
Quality = good pieces ÷ total pieces
OEE = availability × performance × quality

Run time is planned time minus downtime. The ideal cycle time is entered in seconds and converted to minutes before it is compared with run time.

The six big losses and the factor they reduce

Loss	OEE factor	Typical examples
Breakdowns	Availability	Equipment failure, unplanned maintenance
Setups and adjustments	Availability	Changeovers, warm-up, waiting for material
Short stops	Performance	Jams, sensor trips, brief clearing
Reduced speed	Performance	Running below the rated speed
Start-up rejects	Quality	Scrap while the process settles
Production rejects	Quality	Scrap and rework during steady running

Worked example

A machine is planned for 480 minutes and stops for 60, so it runs 420 minutes: availability is 87.5%. At an ideal 30 seconds per piece, the 700 pieces produced need 350 minutes, so performance is 83.3%. Of those 700 pieces, 665 are good: quality is 95%. OEE = 87.5% × 83.3% × 95% = 69%, and the largest loss is performance.

Related guides

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Frequently asked questions

What is a good OEE?

It depends on the process and on how strictly downtime and ideal cycle time are defined. Compare a machine with itself over time, using the same definitions, rather than with a figure from elsewhere.

Is planned maintenance counted as downtime?

Usually not: time with no production planned is left out of planned production time. What matters is applying the same rule every time the OEE is calculated.

What is the difference between OEE and availability?

Availability only measures how long the machine ran compared with what was planned. OEE also counts how fast it ran and how many of the pieces were good.

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