Changeover Time is a critical metric in Lean and manufacturing efficiency.

It is the total duration required to switch a process or machine from producing the last good piece of the previous product to starting to produce the first good piece of the subsequent product.

The changeover period  includes every activity: shutting down the machine, removing old tools, setting up new fixtures, programming, testing, and making necessary adjustments.

Minimizing this time, often using techniques like SMED (Single Minute Exchange of Die), is essential to reducing lot sizes, improving flexibility, and eliminating the Muda (waste) of waiting and inventory, directly enhancing a plant's responsiveness.