Lead Time Calculator
Calculate lead time between order date and delivery date in calendar days, business days, and weeks. Includes average lead time, target delivery date, and safety stock calculator.
Lead Time (calendar days)
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Business Days —
Weeks —
Extended More scenarios, charts & detailed breakdown ▾
Calendar Days
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Business Days —
Weeks —
Professional Full parameters & maximum detail ▾
Inventory Planning
Reorder Point (units) —
Safety Stock (units) —
Avg Inventory During Lead Time —
Lead Time Analysis
Lead Time Variability (CV %) —
How to Use This Calculator
- Enter the Order Date (year, month, day) and Delivery Date.
- Lead time in calendar days, business days, and weeks appears instantly.
- Use the Average Lead Time tab to find mean lead time across 5 orders.
- Use the Target Date tab to calculate expected delivery from order date + lead time.
- The Professional tab calculates reorder point and safety stock.
Formula
Lead Time = Delivery Date − Order Date
Reorder Point = Avg Daily Demand × Avg Lead Time + Safety Stock
Safety Stock = z × σ_LT × Daily Demand
Example
Order Jan 3, Delivery Jan 17: Lead Time = 14 calendar days, 10 business days.
Frequently Asked Questions
- Lead time is the total time from placing an order to receiving delivery. It includes order processing, manufacturing, and shipping time. Shorter lead times improve inventory efficiency.
- Business days are Monday through Friday, excluding weekends. Holidays are not excluded unless specified. Our calculator counts Mon–Fri between the two dates.
- Safety stock is extra inventory kept to buffer against lead time variability and demand uncertainty. Formula: Safety Stock = z × σ_LT × average daily demand, where z is the service level factor.
- Reorder Point = (Average Daily Demand × Average Lead Time) + Safety Stock. When inventory drops to this level, it is time to place a new order.
- Lead times vary widely: printed circuit boards 4–12 weeks, standard components 2–8 weeks, custom parts 6–20 weeks. Supply chain disruptions can extend these significantly.