01
Enter your shift time and planned stops
Start with the total shift length (e.g. 480 min for 8 hours) and subtract scheduled breaks, meals, and planned maintenance. The remainder is your Planned Production Time — the denominator for Availability.
OEE Calculator
Availability, performance, quality, and the Six Big Losses — in one view.
Updated Reviewed by Sajid Hussain· Editor
Try it with your numbers
Results update in real time as you type — no submit needed.
Your numbers
Results
⚡
Results appear as you type
No submit button needed
Why trust this calculator
Last updated
June 3, 2026
Coverage
9 markets · 8 currencies
Privacy
Calculated in-browser · no data stored
Pricing
Free forever · no sign-up
Manufacturing KPI
What is Overall Equipment Effectiveness (OEE)?
OEE is the gold-standard metric for measuring how productively a machine or work cell uses its planned production time. A score of 100% means every minute the line was scheduled to run, it ran at full speed producing only good parts — no breakdowns, no slow cycles, no scrap.
The metric was formalised by Seiichi Nakajima as part of Total Productive Maintenance (TPM) and later standardised in ISO 22400. It decomposes into three independent factors — Availability, Performance, and Quality — so you can pinpoint exactly where losses are happening and calculate the ROI of fixing them.
Most plants run between 40% and 60% OEE without realising it. World-class is 85%. Closing that gap by even 10 percentage points on a high-speed line often equals millions in hidden capacity unlocked with zero capital expenditure.
Quick facts
- World-class OEE
- ≥ 85%
- Typical plant OEE
- 40–65%
- ISO standard
- ISO 22400
- Components
- A × P × Q
- Six Big Losses
- Fully broken down
- Free to use
- No sign-up needed
How It Works
Calculate OEE in Four Steps
02
Enter unplanned downtime
Record every minute the machine was stopped unexpectedly: breakdowns, waiting for materials, tooling changes that ran over schedule. Subtract this from Planned Production Time to get Run Time.
03
Enter ideal cycle time and output counts
Enter the machine's nameplate cycle time in seconds (e.g. 45 s/part), total pieces produced, and how many were defective. Performance compares actual output rate to the ideal rate; Quality measures the good-parts ratio.
04
Read your OEE and loss breakdown
The calculator shows OEE, each of the three factors as a percentage, and a loss breakdown in minutes — so you can see immediately whether Availability, Performance, or Quality is your largest improvement lever.
Steps to use the OEE Calculator: Enter your shift time and planned stops, Enter unplanned downtime, Enter ideal cycle time and output counts, Read your OEE and loss breakdown.
The Formula
OEE Formula Explained
01
Availability
Availability = Run Time ÷ Planned Production Time
Run Time = Planned Production Time − Unplanned Downtime. Planned stops (breaks, scheduled maintenance) are excluded from both numerator and denominator — they are not losses.
Example: 405 min ÷ 450 min = 90.0%
02
Performance
Performance = (Ideal Cycle Time × Total Pieces) ÷ (Run Time × 60)
Compares what the machine actually produced to the theoretical maximum it could have produced at nameplate speed. Capped at 100% — a figure above 1.0 means the ideal cycle time is set too slow.
Example: (45 s × 480 pcs) ÷ (405 min × 60) = 21 600 ÷ 24 300 = 88.9%
03
Quality
Quality = Good Pieces ÷ Total Pieces Produced
Good Pieces = Total Pieces − Defective Pieces. Any part that requires rework counts as a defect for this calculation.
Example: 460 ÷ 480 = 95.8%
04
OEE
OEE = Availability × Performance × Quality
The three factors multiply together. Because of this, a weakness in any single factor pulls down the total disproportionately — 90% × 89% × 96% ≈ 77%, not 92%.
Example: 0.900 × 0.889 × 0.958 = 76.7%
Worked Example
Step-by-Step Walkthrough
Scenario
A machining cell runs an 8-hour shift (480 min) with 30 min of scheduled breaks, 45 min of unplanned downtime, an ideal cycle time of 45 seconds, 480 total pieces produced, and 20 defective pieces.
1
Step 1 · Planned Production Time
480 min shift − 30 min planned stops = 450 min
Planned Production Time = 450 min
2
Step 2 · Run Time and Availability
450 min − 45 min unplanned downtime = 405 min Run Time. Availability = 405 ÷ 450 = 90.0%
Availability = 90.0%
3
Step 3 · Performance
(45 s × 480 pcs) ÷ (405 min × 60) = 21 600 ÷ 24 300 = 88.9%
Performance = 88.9%
4
Step 4 · Quality
480 − 20 defects = 460 good pieces. Quality = 460 ÷ 480 = 95.8%
Quality = 95.8%
5
Step 5 · OEE
Availability 90.0% × Performance 88.9% × Quality 95.8% = OEE 76.7%
OEE = 76.7%
The takeaway
An OEE of 76.7% is in the "good" range (75–85%). The largest loss is Performance (88.9%), suggesting the machine is running slower than its design speed — minor stops or reduced speed cycles are the most likely cause.
Benchmarks
OEE Benchmark Levels
| Metric | Poor | Average | Good | Excellent |
|---|---|---|---|---|
| OEE Score | < 65% | 65–74% | 75–84% | ≥ 85% (world-class) |
| Availability | < 75% | 75–84% | 85–94% | ≥ 95% |
| Performance | < 70% | 70–84% | 85–94% | ≥ 95% |
| Quality | < 95% | 95–98% | 98–99% | ≥ 99.5% |
Comparison
Calcrux OEE Calculator vs Alternatives
| Feature | Calcrux (Free) | Manual Spreadsheet | Siemens Opcenter / SAP ME |
|---|---|---|---|
| Instant OEE calculation | |||
| Three-factor breakdown (A, P, Q) | Manual | ||
| Six Big Losses breakdown in minutes | |||
| Performance-cap warning (bad cycle time) | |||
| Actionable warnings per factor | Varies | ||
| ISO 22400 compliant formulas | Depends | ||
| Cost | Free | Free | 500–5,000 per year |
Common Mistakes
OEE Calculation Mistakes to Avoid
Including planned stops in the downtime figure
Why it matters
Scheduled breaks and planned maintenance are not OEE losses. Adding them inflates unplanned downtime and understates Availability.
Fix
Track planned and unplanned stops separately. Only unplanned events reduce Availability.
Using actual average cycle time as the ideal cycle time
Why it matters
The ideal cycle time must be the theoretical maximum speed (nameplate speed), not what the machine typically achieves. Using the average masks Performance losses.
Fix
Use the machine manufacturer's published cycle time or the fastest sustained rate observed under good conditions.
Counting only scrap — ignoring rework
Why it matters
Parts that need rework also represent lost capacity. OEE Quality must count all first-pass failures, not just scrapped pieces.
Fix
Count every piece that leaves the station without meeting spec on the first pass, even if it is reworked later.
Averaging OEE percentages across shifts
Why it matters
A simple average of OEE scores is mathematically incorrect when shifts have different planned production times.
Fix
Compute OEE per shift, then calculate a weighted average using each shift's Planned Production Time as the weight.
Treating OEE as an absolute target rather than a relative improvement metric
Why it matters
A 95% OEE on a non-bottleneck machine is irrelevant. Over-producing fast runs up WIP inventory and can actually harm flow.
Fix
Focus OEE improvement efforts on the constraint machine (the bottleneck) first. Raising OEE on non-constraints rarely increases throughput.
Pro Tips
How to Use OEE Effectively
Fix the worst factor first
Because OEE is multiplicative, the factor furthest from 100% gives the largest absolute gain when improved. If Availability is 70% and Performance is 95%, a 10-point Availability gain is worth far more than a 10-point Performance gain.
Track OEE in real time
Shift-end OEE is useful for trending, but live OEE lets operators intervene during the shift. Even a simple downtime button on the machine panel dramatically improves data quality and response time.
Start with one machine
Rolling out OEE tracking plant-wide at once creates data-quality problems and change-resistance. Pick your top bottleneck or highest-cost machine, get OEE right there, then expand.
Verify your ideal cycle time
A Performance score above 100% (caught by this calculator's capped-performance warning) is a sign your ideal cycle time is set too slow. Correct it before sharing OEE reports — otherwise every subsequent analysis is wrong.
Add a downtime Pareto
OEE tells you how much you are losing. A downtime Pareto tells you why. Together they let you size an improvement project — calculate the value of the top three downtime causes and prioritise accordingly.
Who Uses This
Who Uses the OEE Calculator
The OEE Calculator works across every stage of the workflow.
Production supervisors
Track shift-by-shift OEE to spot deteriorating availability before it becomes a major breakdown, and share a clear metric with the maintenance team.
Lean / continuous-improvement engineers
Quantify the current-state losses in a VSM (Value Stream Map) and build a business case for a TPM or SMED project by showing the financial value of recovered capacity.
Plant managers
Compare OEE across work cells to identify which machine is the true production bottleneck and where capital investment or headcount will have the highest ROI.
Manufacturing consultants
Run a quick OEE assessment for a new client without needing their MES system — gather shift data in a conversation, enter it here, and show them their loss breakdown in minutes.
Students and trainees
Learn how Availability, Performance, and Quality interact, and see why a weakness in one factor pulls the total OEE down disproportionately — ideal for TPM or lean manufacturing coursework.
Glossary
Key OEE Terms
Every important term you'll encounter in this calculator and the broader topic.
- OEE (Overall Equipment Effectiveness)
- A single percentage that measures how productively a machine uses its planned production time. Defined in ISO 22400 as the product of Availability, Performance, and Quality.
- Availability
- The fraction of planned production time during which the machine was actually running. Lost to unplanned breakdowns, setup overruns, and waiting.
- Performance
- How fast the machine produced parts compared to its theoretical maximum (ideal cycle time). Lost to minor stops, speed reductions, and operator delays.
- Quality
- The fraction of parts produced that passed quality standards on the first pass. Lost to defects, scrap, and rework.
- Ideal Cycle Time
- The theoretical minimum time to produce one good unit — the machine's nameplate or design speed. Must be the fastest possible rate, not the average actual rate.
- Planned Production Time
- Shift time minus all scheduled (planned) stops. This is the time the plant intended the machine to be producing. It is the baseline denominator for OEE.
- Six Big Losses
- The six categories of OEE loss identified in TPM: Equipment Failure and Setup/Adjustment (Availability); Idling/Minor Stops and Reduced Speed (Performance); Process Defects and Reduced Yield (Quality).
- TPM (Total Productive Maintenance)
- A maintenance philosophy developed by Seiichi Nakajima that aims to maximise equipment effectiveness by involving all employees in maintaining and improving machines. OEE is TPM's primary KPI.
Help & answers
Frequently asked questions
Everything you need to know about how the OEE Calculator works.
01What is OEE?
OEE (Overall Equipment Effectiveness) measures how much of your planned production time is truly productive. It multiplies Availability, Performance, and Quality to give a single percentage score for machine efficiency.
02What is the OEE formula?
OEE = Availability × Performance × Quality. Each factor is a ratio from 0 to 1, so a result of 0.85 means 85% of planned production time generated good output at full speed.
03What does 85% world-class OEE mean?
85% is the widely cited world-class benchmark, originally from Seiichi Nakajima's Total Productive Maintenance work. It means 15% of planned production time is lost across all three factors. Few plants sustain it.
04What is ideal cycle time?
Ideal cycle time is the theoretical fastest time to produce one good unit — the machine's nameplate or design speed. Using a cycle time that is slower than actual capability will inflate your Performance score artificially.
05How do I calculate OEE across multiple shifts?
Calculate OEE for each shift separately using that shift's actual downtime and output. Then compute a weighted average by planned production time across shifts. Do not simply average the percentages.
06What is the difference between planned and unplanned downtime?
Planned stops (breaks, scheduled maintenance, changeovers) are excluded from OEE as they are not losses you can eliminate. Unplanned downtime (breakdowns, waiting, starved lines) counts against Availability.
07What are the Six Big Losses in OEE?
The Six Big Losses are: (1) Equipment failure, (2) Setup and adjustment — both hit Availability; (3) Idling and minor stops, (4) Reduced speed — both hit Performance; (5) Process defects, (6) Reduced yield — both hit Quality.
08How can I improve Availability quickly?
Start a downtime log to find the top three failure causes, then apply preventive maintenance on those points. Even moving from reactive to time-based servicing typically adds 5–10 percentage points to Availability.
09Is OEE standardized? Is it related to ISO 22400?
ISO 22400 (Manufacturing Operations Management KPIs) defines OEE and related metrics formally. This calculator follows the ISO 22400 definitions for Availability, Performance, and Quality.
10What are the limitations of OEE?
OEE does not capture throughput rate, cost, or downstream bottlenecks. A single machine with 95% OEE may still constrain a line if it is the bottleneck. Use OEE alongside cycle-time and flow analysis for full picture.
11What is the difference between OEE and TEEP?
OEE measures performance against Planned Production Time (scheduled hours only). TEEP (Total Effective Equipment Performance) measures against calendar time — 24 hours a day, 7 days a week — so it also captures schedule losses. OEE is the more common shop-floor metric.
12Is this OEE calculator free and does it work for any industry?
Yes — fully free, no sign-up required, and calculated entirely in your browser. The ISO 22400 formulas apply to discrete manufacturing, process manufacturing, packaging, and assembly lines worldwide. The inputs and outputs are unit-neutral.
Keep exploring
Related tools
Takt Time Calculator
Set your production pace: takt time, required output rate, and line status.
Open tool
Production Capacity Calculator
Theoretical, effective, and net capacity — for machines, shifts, and efficiency.
Open tool
MTBF & MTTR Calculator
Mean time between failures, mean time to repair, and machine availability.
Open tool
Category
Manufacturing & ERP Operations
Subcategory
production planning
Availability
Global · 9 markets
Price
Free forever
Topics
OEEoverall equipment effectivenessavailabilityperformancequalitysix big lossesISO 22400lean manufacturing
Explore 500+ more tools
Calculators, simulators, and decision tools for every stage of business operations.