OEE Calculator

Overall equipment effectiveness shows how much of your planned production time was productive. Enter one shift's numbers to see availability, performance, quality and the loss that costs you most.

Planned production timeShift length minus planned stopsminUnplanned downtimeBreakdowns, changeovers, waitsminIdeal cycle timeFastest reliable ratesec / unitTotal countEverything producedunitsGood countRight first time, no reworkunits

Your OEE

74.8%

Availability88.8%

Performance86.1%

Quality97.8%

Performance is your weakest factor at 86.1%. Look at small stops and running below ideal speed first.

Where your planned time wentEach loss shortens the bar; what is left is fully productive time.

Planned production time420 min

Run time373 min

Downtime 47

Net run time321 min

Speed loss 52

Fully productive time314 min

Lost minutes: downtime 47 · slow cycles and small stops 52 · defects 7

Example values are filled in. Replace them with your own; nothing you type leaves your browser.

Worked example

The example values, step by step

Step 1 · Run time
420 planned min − 47 min downtime
= 373 min
Step 2 · Availability
373 ÷ 420
= 88.8%
Step 3 · Ideal run time
19,271 units × 1.0 s ÷ 60
= 321.2 min
Step 4 · Performance
321.2 ÷ 373
= 86.1%
Step 5 · Quality
18,848 good ÷ 19,271 total
= 97.8%
Step 6 · OEE
0.888 × 0.861 × 0.978
= 74.8%

Reading the result

In the example, about 314 of 420 planned minutes were fully productive. Downtime cost 47 minutes, slow cycles and small stops about 52, and defects about 7.

So speed losses and downtime are the places to look first. Read the three factors as well as the total, because the same OEE can hide very different problems.

Where the six major losses land

Factor	Losses
Availability	Failures; setups and adjustments
Performance	Minor stoppages; reduced speed
Quality	Scrap; rework

Common data mistakes

Setting the ideal cycle time too slow, which inflates performance.
Counting changeovers as planned downtime on some shifts and as losses on others.
Counting reworked parts as good on the first pass.

The methods behind the number

The formula

How it's calculated

Availability: Run time ÷ Planned production time
Performance: (Ideal cycle time × Total count) ÷ Run time
Quality: Good count ÷ Total count
OEE: Availability × Performance × Quality

Start with the constraint

Measure OEE on the machine that limits the output of the whole line first. Raising OEE anywhere else adds capacity the line cannot use.

Read the factors, not just the total

Two lines with the same OEE can have completely different problems. Low availability points to breakdowns and changeovers; low performance to small stops and slow running; low quality to scrap and rework.

Define the terms once

Agree what counts as planned downtime and what ideal cycle time means for each product. If those definitions change, the trend becomes meaningless.

Frequently asked questions

What is a good OEE score?

There is no universal answer, because it depends on the industry, the product mix and how losses are defined. Compare each line with its own history and focus on the trend.

Should planned maintenance count as downtime?

Most definitions exclude planned stops, such as scheduled maintenance or no demand, from planned production time. Whatever you choose, apply it consistently.

Why is my performance over 100%?

The ideal cycle time is probably set too slow. It should be the fastest the machine can reliably run the product, not the usual speed.

How do you calculate OEE?

Multiply availability by performance by quality. Availability is run time over planned time, performance is ideal cycle time times total count over run time, and quality is good count over total count.

How do I find the ideal cycle time?

Use the fastest rate the machine can reliably run for that product, such as the design or nameplate rate. Keep the same value over time, or the trend means nothing.

Can OEE be calculated for a whole line?

Yes. Many plants measure the line at its constraint, because the constraint sets the output of the whole line.

Sources and further reading

Lean Enterprise Institute lexicon: overall equipment effectiveness ↗
Seiichi Nakajima, Introduction to TPM (book)

For vendors

Built a lean tool?

Submit it for review. Every tool is checked against our listing criteria and researched from public sources. Approved tools join their category in the next published batch.

Get listed How we research