Flow Efficiency: how much work flows vs. waits
Most of the delivery time is not work: it is waiting in queues. Adjust the WIP below, measure flow efficiency and watch an item’s journey split into what is active and what is queue.
Flow efficiency measures how much of an item’s total time is active work, not idle waiting in queues. Adjust the WIP and discover how little is actually work.
What flow efficiency is
Flow efficiency is the fraction of the lead time in which the item is actually receiving active work, rather than sitting idle. The math is simple: active time ÷ total lead time (active + waiting).
It is the metric that exposes the gap between being busy and flowing: an item can be “in progress” for days without anyone touching it: it just occupies a column, waiting.
Why it is usually so low
Intuition expects something high, but in practice flow efficiency usually lands between 15% and 40%. The reason: an item spends most of its life in queues: between stages, awaiting review, blocked by a dependency or a handoff to someone else.
The more items in parallel (high WIP) and the more handoffs, the more waiting points pile up. Real active work barely changes; what grows is the idle queue time, and efficiency collapses.
How to raise it (less WIP, fewer handoffs)
Flow Efficiency = Active time ÷ Lead time
Since the numerator (active work) is nearly fixed, the lever is the denominator: cut the waiting. Less WIP shortens the queues between stages; fewer handoffs remove waits on other people; clearing blockers fast returns the item to flow. That is how the gray waiting band shrinks and efficiency rises.
Frequently asked questions about flow efficiency
What is flow efficiency in Kanban?
It is the fraction of the lead time in which the item receives active work, rather than sitting idle. It is computed as active time ÷ total lead time (active + waiting).
Why is flow efficiency usually so low?
Because most of the lead time is waiting: queues between stages, handoffs and blockers. Values between 15% and 40% are common even in busy teams.
What is the difference between flow efficiency and lead time?
Lead time is the total time, from arrival to delivery. Flow efficiency is how much of that time was actually active work: it separates being busy from flowing.
How do you raise flow efficiency?
By cutting the waiting: less WIP shortens the queues, fewer handoffs remove passes between people, and clearing blockers fast returns the item to flow.
Enjoyed learning by doing?
Take flow to the next level: manage a squad in the Kanban Game.
