Little’s Law


The formula for Little’s Law

Little’s Law is expressed through the following equation:

 L=λ .W

 In the above equation

L – the average number of items in a queuing system

λ – the average number of items arriving at the system per unit of time

W – the average waiting time an item spends in a queuing system

Example of Little’s Law

Sia owns a small beverage shop. She wants to know the average number of customers queuing in her beverage shop so that she can decide whether to add more space to comfort more clients. Currently, her queuing area can accommodate no more than 20 customers.

Sia estimated that on average, 50 customers visit at her beverage shop every hour. She also determined that on average, a customer spends about 10 minutes in her shop (or 0.16 hours). Given the figures, Sia can find the average number of the customers queuing in her beverage shop by applying the Little’s Law:

L = 50 x 0.16 =  8 customers

The Little’s Law determines that on average, only 8 customers are queuing in Sia’s beverage shop. Therefore, she does not require to create more space in her store to serve more queuing customers.