Logistics & Supply Chain
Intermediate
Little's Law
Average items in a system equals arrival rate times average time in the system.
Formula
Variables
LItems in system
\lambdaArrival rate
WAverage time in system
Example
λ=30/hr, W=0.5 hr: L = 15 items
Did You Know?
Little's Law holds for any stable queue regardless of the arrival pattern — a remarkably general result.
Share this formula
More in Logistics & Supply Chain
View allEconomic Order Quantity
IntermediateOrder size that minimises the combined cost of ordering and holding stock.
Reorder Point
BasicStock level that triggers a new order, covering demand during the lead time.
Safety Stock
AdvancedBuffer inventory that absorbs demand variability during lead time.
Inventory Turnover
BasicHow many times inventory is sold and replaced in a period.
Days Inventory Outstanding
BasicAverage number of days stock sits before being sold.
Cycle Stock
BasicAverage working inventory between deliveries, half the order quantity.