Leadership, teams & operations · law 099
Little's Law
By Shivam Bhandari · Reviewed 31 October 2026 · How we write
what it means
Average work in progress equals throughput multiplied by average time each item spends in the system (L = λW).
How Little's Law works
If a clinic sees 10 patients an hour and each spends 30 minutes there, about 5 patients are inside at any time. Change any two numbers and the third follows.
The business insight: to make things faster (shorter lead time), you either increase throughput or reduce work in progress. Starting more jobs at once usually makes everything slower.
where it comes from
Operations researcher John D. C. Little published the proof in 1961. It is now a foundation of queueing theory, lean manufacturing, and service operations.
Little's Law examples in business
Manufacturing
A workshop with 60 jobs open and finishing 10 a day has an average lead time of six days; cutting open jobs to 30 halves it.
Agencies
An agency juggling 20 projects with the same team delivers each one slower than if it took on 10 at a time.
Retail
Restaurants use it to estimate wait times and table needs.
How to apply it
- 1Measure your work in progress, throughput, and lead time.
- 2To cut lead time, limit how many jobs are open at once.
- 3Increase throughput by fixing bottlenecks.
- 4Use the formula to plan staffing and capacity.
common misreading
It describes averages in a stable system; it won't predict every individual job's time.
ask yourself
How many jobs do you have open right now, and is that slowing everything down?
put it into practice
Frequently asked questions
What is Little's Law?
Average work in progress equals throughput multiplied by average time each item spends in the system (L = λW). If a clinic sees 10 patients an hour and each spends 30 minutes there, about 5 patients are inside at any time. Change any two numbers and the third follows.
Who came up with Little's Law?
Operations researcher John D. C. Little published the proof in 1961. It is now a foundation of queueing theory, lean manufacturing, and service operations.
How do you apply Little's Law in business?
1. Measure your work in progress, throughput, and lead time. 2. To cut lead time, limit how many jobs are open at once. 3. Increase throughput by fixing bottlenecks. 4. Use the formula to plan staffing and capacity.
What is a common misunderstanding of Little's Law?
It describes averages in a stable system; it won't predict every individual job's time.