Littles Law Formula :

Littles Law is a theorem that determines the average number of items in a stationary queuing system based on the average waiting time of an item within a system and the average number of items arriving at the system per unit of time.

Formula to Find WIP :

WIP = Cycle Time × Throughput Volume Per Unit of Time

Formula to Find Throughput :

Throughput = WIPCycle Time

Formula to Find Cycle Time :

Cycle Time = WIPThroughput Volume Per Unit of Time

Where,

WIP - Work-In-Process

Example :

Mr. Obama owns a small juice shop.Currently, his queuing area can accommodate no more than 8 customers.He wants to know the average number of customers queuing in his juice shop to decide whether he needs to add more space to accommodate more customers.

Mr. Obama measured that on average, 40 customers arrive at his juice shop every one hour and his customer spends around 6 minutes (or 0.1 hours).

Given the inputs, Mr. Obama can find the average number of the customers queuing in his juice shop by applying the Littles Law:

WIP = Cycle Time × Throughput Volume Per Unit of Time

WIP = 0.1 hours × 40 customers = 4 customers

so, Mr.Obama needs to add more space to accommodate 4 more customers in his juice shop.