Process Cycle Efficiency Calculator
Process cycle efficiency — the share of a process’s lead time that actually adds value — with the waiting and non-value time it exposes and how the figure compares with lean benchmarks.
Walk the process and add up the time a unit is actually being worked on in a way the customer pays for: that is value-added time.
How the process cycle efficiency calculator works
Walk the process and add up the time a unit is actually being worked on in a way the customer pays for: that is value-added time. Divide by the total lead time from start to finish, waiting included. Most processes come out at 1–10%; a lean process reaches 25%. The gap is queues, transport, inspection and rework — the targets for improvement.
Formula: PCE = value-added time ÷ total lead time × 100
Worked examples
| Inputs | Process cycle efficiency | Note |
|---|---|---|
| 45 minutes of work in a 5-day lead time | 0.63 % | 0.63% |
| 2 hours of work in 8 hours | 25 % | 25% — lean |
| 3 days of work in 30 days | 10 % | 10% |
FAQFrequently asked questions
What counts as value-added?
Work that changes the product in a way the customer would pay for and is done right first time: machining, assembling, writing the code. Inspection, moving, waiting, rework and approvals are non-value-added even if some are necessary.
Why are the numbers so low?
Because units spend most of their life in queues — between steps, in batches, waiting for a machine or a signature. A part with an hour of machining that takes two weeks to ship is at 0.3%.
What is a good target?
George’s Lean Six Sigma benchmark: 25% for machining and 30% for assembly and transactional processes is world-class; 10% is good; typical is 1–5%. Halving the queues usually doubles the efficiency.
How do I improve it?
Cut batch sizes, balance the steps so nothing waits, pull rather than push, and remove approvals that add no value. Lead time falls while value-added time stays the same — the metric shows it directly.
Where these figures come from
- Nakajima (1988) — Introduction to TPM — the origin of Overall Equipment Effectiveness and its six big losses
- Health and Safety Executive — the UK workplace safety regulator
Last checked: September 2026. Definitions follow standard operations-management practice; where plants commonly differ, the page says so.