Understanding your result
OEE measures fully productive time as a share of planned production time. The four bars reconcile that period into stops, speed loss, quality loss at ideal speed, and good production at ideal speed. Quality-loss minutes are an equivalent at the ideal cycle, not a measured scrap-handling duration.
To compare a process pace with customer demand, use the Takt Time Calculator which answers a different question from equipment effectiveness.
The formula
Run time equals planned time minus stops. Convert ideal cycle seconds to minutes before multiplying by counts. Factors are multiplied as fractions, then expressed as percentages. When no parts are produced, quality has no denominator and is labeled undefined, while fully productive time and OEE remain zero.
Worked example
A 480-minute planned period with 60 minutes stopped has 420 minutes running. At a 30-second ideal cycle, 700 units represent 350 ideal minutes and 665 good units represent 332.5 minutes. Availability is 87.5%, performance 83.33%, quality 95%, and OEE 69.27%. Losses are 60 stop, 70 speed, and 17.5 quality minutes.
How to use this calculator
- Use a consistent planned production period and its included stop time.
- Enter the ideal cycle in seconds and total produced units.
- Enter first-pass good units and inspect the factors and reconciled time losses.
Define planned time consistently
This tool accepts planned production time after your organization has defined what belongs in the period. Apply the same rules to breaks, changeovers, and scheduled production across comparisons. Altering the denominator can change the score without changing the physical process.
Use an ideal cycle, not an average observed cycle
An average cycle can already contain speed losses and conceal them. The ideal cycle should represent the benchmark appropriate to this product and process. A combination implying performance above 100% is rejected so you can correct the cycle, counts, or timing instead of hiding the inconsistency.
Read the factors alongside the total
Multiplication means three moderately strong factors can still produce a much lower combined percentage. A rising total can also conceal a decline in one factor. The calculator does not attach universal target labels, identify causes, or forecast production; it summarizes the measurements you entered.
Assumptions & limitations
What this calculation assumes
- The same ideal cycle applies to all units in the period; good units are first-pass good units.
What to keep in mind
- Mixed-product cycles, rework routing, and shift scheduling require a more detailed model.
Common questions
What if the equipment never ran?
Enter zero total and good units. OEE and availability are zero; performance and quality have no valid denominator and are labeled accordingly.
Why are losses shown in minutes?
It puts all losses on the same planned-time basis and makes the total checkable. These equivalent minutes should not be confused with separate stopwatch observations.