Cycle Time

Definition

The elapsed time required to complete one unit of production at a given step or through the entire process. Three commonly-confused variants — be explicit which:

• Ideal Cycle Time — engineering spec, the fastest possible time per part at design conditions. Used in OEE Performance calculation.
• Actual Cycle Time — observed average time per part during real production.
• Throughput Cycle Time (a.k.a. Flow Time / Lead Time per unit) — time from raw material entering the line to finished part exiting.

Formula

Actual Cycle Time = Run Time / Total Count
Throughput Cycle Time = WIP × Cycle Time  (Little's Law inverse)

Required data

• Run time (production minutes excluding planned downtime)
• Total count (parts completed)
• For throughput cycle time: WIP (work in progress) snapshot

Possible data sources

• PLC part counter + machine state
• MES production order start/end
• RFID or barcode at line entry + exit

Factory example

Stamping press, ideal CT = 12 sec/part. Actual run: 390 min, 1700 parts → Actual CT = 390 × 60 / 1700 = 13.76 sec/part.

Gap of 1.76 sec/part → Performance = 12 / 13.76 = 87.2% (matches OEE example).

Economic impact

• The gap between ideal and actual = recoverable performance (no capex)
• Cycle time vs Takt Time tells you whether you can meet demand
• Drives shift-staffing and line-balancing decisions

Common mistakes

• Mixing the three variants without labels → arguments
• Using “average” cycle time when distribution is bimodal (e.g. before/after changeover) → misleading
• Ignoring micro-stops → actual CT looks better than it is
• Reporting in different units across teams (sec vs min vs parts/hr)

See also

• OEE · Takt Time · First Pass Yield
• Factory Physics — Hopp & Spearman, Ch 1–7
• NOTQIN Industrial Intelligence Operating Thesis 2026 §5 Stage 1