Process Time

Process time measures how long one unit takes to move through a single step from start to finish, assuming the worker is actively processing it without interruptions. It’s measured in minutes (or hours) per unit and is the most fundamental building block of process measurement, every other metric derives from it.

Process time does not include waiting, delays, or time spent in a queue. It captures only the hands-on work. A clerk who takes 6 minutes to review one application has a process time of 6 minutes, regardless of whether the application sat in an inbox for two days before being picked up.

Note on “Cycle Time”: This term is used inconsistently across disciplines. In Lean and manufacturing, cycle time typically means the same as process time (time per unit at one step). In some Six Sigma and service operations contexts, cycle time means flow time (total elapsed time through the entire system). This glossary uses “process time” to avoid ambiguity.

Formula

Process time is measured directly, observed or estimated, not calculated from other values.

Example

A loan application review takes 15 minutes per application. The process time (p) is 15 minutes. If the same person reviewed 4 applications in an hour, each taking 15 minutes, the process time is still 15 minutes, the fact that they did four doesn’t change how long each one takes.

Why It Matters

Process time is the denominator behind process rate and capacity. Reducing process time at the bottleneck directly increases the capacity of the entire process. Reducing it anywhere else may free up resources but won’t increase output until the bottleneck is addressed. When measuring process time in people-driven environments, be cautious about “padded” times, people may appear busy for longer than the actual work requires (Parkinson’s Law: work expands to fill the time available).