How this calculation works
Calculate the three factors on one production boundary. Do not silently cap an above-100% performance result. Distinguish zero output from an undefined first-pass quality rate and preserve a direct productive-time ratio.
OEE = availability × performance × first-pass quality = ideal cycle × first-pass good count / planned timeA worked example
480 planned minutes with 60 stopped leaves 420 running. At 30 ideal seconds/unit, 700 total units and 665 first-pass good, availability is 87.5%, performance about 83.3333%, quality 95% and OEE about 69.270833%.
Good to know
Single product and fixed ideal cycle over one interval. Good units exclude reworked units. No benchmark, mixed-product adjustment or equipment/personnel rating. Inconsistent above-100% performance is exposed and its loss chart omitted.
Reference: Reference: model definitions and scope (opens in a new tab) ↗
Availability performance and quality measure separate losses
The default 480 planned minutes minus 60 stopped gives 420 minutes running, or 87.5% availability. Seven hundred units at a 30-second ideal cycle represent 350 ideal minutes, giving about 83.3333% performance. Of those 700 units, 665 pass first time, giving 95% first-pass quality.
Multiplying the three factors gives about 69.270833% OEE. The equivalent direct check is 665 × 0.5 ideal minutes divided by 480 planned minutes. The decomposition explains why one percentage alone does not identify the source of lost productive time.
The first pass yield and rework calculator keeps recovered output separate from first-pass success. OEE uses first-pass good output for its quality factor.
First-pass good units exclude later recovered output
A reworked unit may eventually be accepted, but that does not make its original run a first-pass success. Enter the count that passed without rework in this OEE model. The first pass yield and rework calculator can separately track accepted cohort output after recoveries.
The planned interval must already use the production boundary you intend. Stop time is then subtracted once. If breaks have already been excluded from planned time, subtracting them again as stop time would double count the exclusion. Mixed products with different ideal cycles require a different weighting process.
An above-100% factor is evidence to review the inputs
If ideal cycle times total 350 minutes but only 300 run minutes are entered, performance exceeds 100%. The calculator preserves and flags that result instead of capping it. It omits a positive-only loss chart because the computed speed-loss equivalent is negative.
With no output, the direct productive-time OEE is zero but a quality rate with total count zero is undefined. The takt time and capacity calculator answers a different question about customer pace and expected capacity. Neither tool supplies an industry benchmark or a rating of a particular machine, shift or worker.
A few questions, answered
Should recovered rework count as first-pass good?
No. This OEE definition uses units that passed the first time without rework.
Why is performance above 100% left visible?
It usually indicates a mismatched ideal cycle, run time or output count. Capping it would hide the inconsistency.
What if nothing was produced?
OEE is zero through the productive-time ratio. First-pass quality is undefined when total count is zero; performance also needs positive run time.
Does a particular OEE imply a universal good or bad rating?
No. No benchmark or equipment/workforce judgment is applied.