Lead time calculator
Calculate total order-to-delivery lead time, break it into procurement, production, and shipping components, and pinpoint where delays hide.
Lead time is the total elapsed time from when a customer places an order to when they receive the finished product. It includes procurement lead time (ordering and receiving raw materials), manufacturing lead time (production queue time plus processing time), and delivery lead time (packaging, shipping, and transit). Shorter lead times improve customer satisfaction, reduce inventory carrying costs, and increase competitiveness. Most manufacturers find that over 80% of lead time is non-value-added waiting and queue time — not actual processing.
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Frequently Asked Questions
What is the difference between lead time and cycle time?+
Lead time measures the full duration from order placement to delivery — it includes waiting, procurement, production, inspection, and shipping. Cycle time measures only the active processing time at a single workstation or the total production time on the shop floor. Lead time is always longer than cycle time because it encompasses all the non-processing delays. Reducing cycle time helps, but attacking queue times and procurement delays often yields larger lead time reductions.
How can I reduce manufacturing lead time without increasing costs?+
Focus on eliminating non-value-added time: reduce batch sizes to cut queue time, implement pull systems (kanban) to prevent WIP buildup, cross-train operators to eliminate waiting for specialists, improve setup times with SMED techniques, and co-locate sequential process steps. These lean methods typically reduce lead time by 30–60% with no capital investment because they attack waiting and transport time, not processing time.
How does lead time affect inventory levels?+
Longer lead times require higher safety stock to buffer against demand variability during the replenishment window. The safety stock formula scales with the square root of lead time, so doubling lead time increases required safety stock by roughly 41%. Reducing lead time directly lowers the inventory needed to maintain the same service level, freeing working capital and reducing storage costs.
What is cumulative lead time and why does it matter for planning?+
Cumulative lead time (also called critical-path lead time) is the longest chain of dependent lead times from raw material procurement through all manufacturing stages to finished product delivery. It determines your planning horizon — you cannot promise delivery faster than your cumulative lead time unless you hold strategic inventory. MRP and ERP systems use cumulative lead time to schedule purchase orders and production orders backward from the required delivery date.
How should I account for supplier lead time variability?+
Track actual supplier lead times over at least 6–12 months and compute the mean and standard deviation. Use the mean plus a safety margin (typically 1–2 standard deviations) as your planning lead time. For critical materials, dual-source to reduce dependency risk. Supplier scorecards that track on-time delivery percentage and lead time consistency help you negotiate improvements and decide when to qualify alternative suppliers.