Supplier lead time is the amount of time that elapses between when a buyer places a purchase order with a supplier and when the ordered goods arrive at the buyer's facility. It is a key input in inventory planning, reorder point calculations, and safety stock determination.
Understanding Supplier Lead Time
Supplier lead time is one of the most important variables in inventory management. It determines how far in advance a company must place orders to avoid running out of stock. A supplier with a 2-week lead time requires a very different ordering strategy than one with a 10-week lead time.
Lead times are rarely fixed. They vary based on supplier capacity, production schedules, raw material availability, transit times, and seasonality. CPG brands that rely on accurate lead times for planning need to track actuals over time and update their planning assumptions when lead times change.
Long or unpredictable lead times increase the amount of safety stock a company needs to carry. Reducing lead time is therefore one of the most direct ways to reduce inventory carrying costs.
Core Components of Supplier Lead Time
Supplier lead time is composed of several distinct components. Order processing time is the time the supplier takes to acknowledge the order, allocate capacity, and begin production or fulfillment. Production or manufacturing time is the time required to produce or assemble made-to-order items. Quality inspection time covers checks before shipment, done by the supplier, a third party, or the buyer. Transit time is the time goods spend in transit, including customs clearance for international shipments. Receiving and processing time is the time to unload, inspect, and put away goods before the stock is available for use.
Managing Supplier Lead Time in Practice
To accurately plan inventory, procurement and supply chain teams track lead times for each supplier and item combination. Actuals are recorded in the ERP at the time of each goods receipt by comparing the PO issue date with the GR date.
Over time, these actuals build a lead time history used to calculate average lead times and lead time variability. Highly variable lead times require more safety stock than stable ones.
When planning reorder points, the formula incorporates lead time: Reorder Point = (Average Daily Demand x Lead Time) + Safety Stock.
DOSS and other CPG inventory platforms allow teams to assign lead times by supplier and item, automate reorder point calculations, and flag purchase orders at risk of arriving late based on current supplier performance data.
Related Concepts
- Safety Stock is a buffer of inventory held to protect against lead time variability and demand uncertainty.
- Reorder Point is the inventory level that triggers a new purchase order, calculated using lead time as a key input.
- Goods Receipt is the event that marks the end of the lead time cycle and is used to calculate actual lead times.
- Vendor Scorecard : on-time delivery and lead time adherence are commonly tracked supplier performance metrics.
- Procurement is the function responsible for managing supplier relationships and lead time expectations.
