⚙️ Lean Architect · Tyshchenko Lean Academy

OEE / Overall Equipment Effectiveness

Overall Equipment Effectiveness — an absolute measure of performance compared with the ideal

What OEE is

OEE is the ratio of value-adding time to planned production time. Unlike traditional systems (which compare actuals with a budget), OEE compares against the absolute ideal.

THE OEE FORMULA
OEE
Result
=
A
Availability
×
P
Performance
×
Q
Quality
For example: 84% × 83% × 86% = 59.9% OEE
🟢 Availability
Run time / Planned time

Shows how much of the planned time the equipment actually ran. These losses reduce availability:

Breakdowns — unplanned stops due to failures
Changeovers — stops during setup
Planned maintenance — preventive maintenance
A = 84% → 100% − 84% = 16% lost
Changeovers 7% · Breakdowns 5% · Maintenance 4%
🟡 Performance
Ideal CT × Count / Run time

Shows whether the equipment runs at its ideal speed. These losses reduce performance:

Reduced speed — equipment runs slower than standard
Organizational downtime — late starts, waiting for materials
Minor stops — jams, micro-stops under 5 min
P = 83% → 17% to organizational losses
Reduced speed 10% · Downtime 7%
🟣 Quality
Good units / Total count

Shows what share of the output is good product. Two kinds of quality losses:

Startup defects — before stable running begins
Process defects — during normal production
Q = 86% → 14% scrap and rework
Process defects 9% · Startup 5%
OEE benchmarks — where are you now?
≤40%
Critically low
Serious problems. Needs top-priority attention now
40–60%
Below average
Typical for plants without Lean. Big potential
60–75%
Fair
Lean is in place. There’s room in all three components
75–85%
Good
Mature Lean. Keep working on the bottlenecks
85%+
World Class ⭐
Toyota, Danaher. The benchmark for best-in-class
💡 Architect’s tip: If OEE = 60%, the equipment is effectively productive for only 60% of the planned time. The other 40% is lost to Availability, Performance, or Quality. Every point of OEE is real money.
🧮 Calculating OEE

Enter the equipment data — the calculator works out OEE automatically and shows where the biggest losses are.

🟢 AVAILABILITY
e.g., an 8-hour shift = 480 min
unplanned stops
setup
scheduled maintenance
🟡 PERFORMANCE
theoretical minimum
including defects
🟣 QUALITY
no defects or rework
Defects = Actual − Good
—
Availability
—
Performance
—
Quality
—
OEE
🏭 Practice task — a ready-meals line
LINE DATA FOR ONE SHIFT (8 HRS)
TIME
Planned shift time: 480 min · Breaks: 40 min · Planned run time: 440 min
STOPS
Depositor breakdown: 42 min · Changeover (product change): 23 min · Planned maintenance: 12 min
Total stops: 77 min
OUTPUT
Actually produced: 4,182 lb · Ideal rate: 12 lb/min
Standard pace: we expect 1 lb every 5 sec when running ideally
QUALITY
Accepted product: 4,057 lb · Rejected (out of spec): 125 lb
Startup rejects after the changeover: ~40 lb of the 125 lb
1
Calculate Availability
A = Run time / Planned time = (440 − 77) / 440 = ? %
440 min (plan) − 77 min (stops) = 363 min of run time
A = %
2
Calculate Performance
P = (Ideal CT × Count) / Run time = (12 lb/min × 363 min ≠ 4,182 lb) → P = 4182 / (12 × 363) = ?
Ideal output in 363 min: 12 × 363 = 4,356 lb. Actual: 4,182 lb
P = %
3
Calculate Quality
Q = Good / Total = 4057 / 4182 = ? %
Q = %
4
Calculate OEE and set the improvement priority
OEE = A × P × Q = 82.5% × 96.0% × 97.0% = ? %
OEE = %
5
What do we attack first, and why?
A = 82.5%, P = 96.0%, Q = 97.0%. Which component is lowest? What’s the specific cause? What should we do?