Teams & projects
Cycle time calculator
Enter how many items are in progress and how many your team finishes per week to get the average cycle time, plus the WIP limit that would meet your target.
Use an average throughput over several weeks and count WIP at the same point every time, for example every Monday morning.
How cycle time follows from Little's law
Little's law, proved by John Little in 1961, says that in a stable system the average number of items in progress equals the arrival rate multiplied by the average time each item spends inside. For a team board it is usually written as cycle time = WIP ÷ throughput. Count the items that have been started but not finished, divide by the number of items finished per week, and you get the average time an item takes from start to done, in weeks. Multiplying by 5 working days, or 7 calendar days, converts it to days.
Example: 12 items in progress and a throughput of 8 per week give 12 ÷ 8 = 1.5 weeks, which is 7.5 working days per item. That team finishes 1.6 items a day. To reach a 5-day cycle time with the same throughput, WIP must fall to 5 × 1.6 = 8 items, so finishing 4 items before pulling new ones would do it. The formula works the same in reverse: if you know the cycle time and throughput, their product is the WIP the board should show.
| WIP | Throughput per week | Cycle time (weeks) | Working days |
|---|---|---|---|
| 5 | 10 | 0.5 | 2.5 |
| 10 | 10 | 1 | 5 |
| 20 | 10 | 2 | 10 |
| 15 | 5 | 3 | 15 |
| 30 | 6 | 5 | 25 |
What the number tells you
The main lesson of the law is that, at a given throughput, cycle time rises in direct proportion to WIP. Starting more work does not make anything finish sooner; it only makes every item wait longer. That is why Kanban teams set WIP limits per column, and why lowering WIP is usually the fastest way to shorten delivery times without anyone working harder.
The law holds for averages over a period in which the system is roughly stable: items arrive at about the rate they leave, WIP is not growing or shrinking sharply, and everything started is eventually finished or explicitly removed. If the board fills up week after week, the result understates real cycle time. Averages also hide spread; one stuck item can sit for weeks while most finish in days. For commitments to customers, track the actual start and finish date of each item and quote a percentile, such as "85% of items finish within 9 days", alongside this average.
Frequently asked questions
What is the formula for cycle time?
With Little's law, average cycle time = average work in progress ÷ average throughput. 12 items in progress and 8 finished per week give 1.5 weeks, or 7.5 working days.
What is the difference between cycle time and lead time?
Lead time is measured from when the request is made, cycle time from when work actually starts on it. Lead time includes the waiting time in the backlog, so it is always at least as long.
How do I reduce cycle time?
Lower WIP: finish items before starting new ones and set limits on how many can be in each stage. Removing blockers and waiting time between stages helps more than trying to work faster.