Calculate your OEE — and see which of the three losses is eating it.

Enter one shift's numbers and this free OEE calculator works through the standard calculation steps — availability × performance × quality — showing every intermediate figure, so you can rebuild it in your own sheet. No sign-up, nothing leaves your browser.

Your shift numbers

Inputs

Planned production time (minutes) Shift length minus planned breaks/planned maintenance. 8h shift = 480. Unplanned downtime (minutes) Breakdowns, changeovers over allowance, waiting, micro-stops you can log. Ideal cycle time (seconds per unit) The design/best demonstrated rate — not the average you usually run. Total units produced Good units (first pass) Exclude rework and rejects — rework counted as "produced" hides quality loss.

Result

Your OEE

—

enter your numbers

Step	Formula	Value

World-class is commonly quoted as 85% for discrete manufacturing; a typical unmeasured plant sits nearer 40–60%. The first measured week is usually lower than everyone expected — that's normal, and it's the point.

Free templates

Downtime tracking sheet & OEE calculation template

Both download as CSV and open straight into Excel, Google Sheets or LibreOffice. The downtime log gives you reason codes worth trending; the OEE sheet contains the same calculation steps as the tool above, one row per shift.

Download downtime tracking sheet (CSV) Download OEE calculation sheet (CSV)

Free to use and adapt. If the manual sheet becomes the bottleneck — someone typing it up every shift, numbers nobody quite trusts — that's the moment automatic machine data collection starts paying for itself.

Frequently asked

OEE calculation questions.

Deeper reading: what an OEE system costs and measuring OEE on an old line.

Four steps. 1) Availability = run time ÷ planned production time, where run time = planned time − unplanned downtime. 2) Performance = (ideal cycle time × total units) ÷ run time. 3) Quality = good units ÷ total units. 4) OEE = availability × performance × quality. The calculator above shows each intermediate value so you can audit it.

85% is the commonly quoted world-class benchmark for discrete manufacturing, 60% is a reasonable "measured and managed" level, and 40% or below is common for plants measuring for the first time. Treat the benchmark loosely — the useful comparison is your own line, week on week, after each fix.

Your ideal cycle time is set too slow — often it's the average rate rather than the design rate. Performance above 100% means the "ideal" isn't ideal; correct it to the design or best demonstrated rate, or speed losses stay invisible.

You can start there — the templates on this page are exactly that. In practice manual sheets decay: entries drift to end-of-shift memory, micro-stops go unrecorded, and the numbers stop being trusted. Once decisions hang on the data, automatic collection (counters, current clamps, PLC reads) is what keeps it honest — that's our OEE management and machine retrofit work.

Want this number on a screen, automatically, every shift?

We instrument the line — old or new, with or without a PLC — and OEE calculates itself from real machine data. Indicatively from ~ZAR 60 000 per line.

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