Definition
Lead time is the total elapsed time between initiating a process and completing it. In supply chain and inventory management, lead time typically refers to the time between placing a purchase order and receiving the goods. It includes supplier processing time, manufacturing time (if applicable), transit time, and receiving time at the destination warehouse.
Understanding Lead Time
Lead time is one of the most consequential variables in inventory management. It determines how far in advance companies must plan their orders, how much inventory they need to hold, and how responsive they can be to demand changes.
Short lead times give operations teams flexibility. When a supplier can deliver in 3 days, companies can order more frequently in smaller quantities, reducing carrying costs and the risk of obsolescence. Long lead times require larger safety stock buffers and more advanced demand forecasting.
The challenge for CPG brands is that lead times are rarely fixed. Suppliers face their own production schedules, shipping delays, customs clearance, and port congestion. Treating lead time as a single number rather than a range leads to miscalculated safety stock and poorly timed purchase orders.
Core Lead Time Components
- Supplier Lead Time: The time from placing an order to the supplier shipping it. Includes order confirmation, production scheduling, and manufacturing or picking time.
- Transit Time: The time goods spend in transport from the supplier's location to the buyer's receiving facility. Influenced by shipping method, distance, and carrier reliability.
- Receiving and Processing Time: The time required to unload, inspect, and put away inventory after it arrives. Often overlooked but can add 1-3 days to effective lead time.
Types of Lead Time
Supplier Lead Time: Time from purchase order to shipment from the supplier. The most commonly tracked form of lead time.
Manufacturing Lead Time: Time required to produce goods from raw materials to finished product. Relevant for brands with contract manufacturing or in-house production.
Customer Lead Time: Time from a customer placing an order to the customer receiving it. Relevant for DTC and B2B fulfillment operations.
Cumulative Lead Time: The total time to fulfill an order if all materials must be sourced from scratch, with no inventory on hand. Used in planning for new product launches and supply chain risk assessment.
Related Concepts
- Safety Stock : Reserve inventory held to absorb lead time variability. Longer and more variable lead times require more safety stock.
- Reorder Point (ROP) : Calculated using average lead time. Accurate lead time data is essential for setting effective reorder points.
- Demand Planning : Forecasting future demand over the lead time window. The further in advance orders must be placed, the more accurate forecasts must be.
- Landed Cost : The total cost to receive goods, including shipping. Longer lead times often correlate with lower per-unit shipping costs but higher inventory carrying costs.
