# Lead Time Calculator

Calculate total lead time for your supply chain from order to delivery. Find your reorder point and safety stock levels to prevent stockouts.

## What this calculates

Lead time is the total number of days from placing an order to receiving the goods. This calculator adds up every step (processing, manufacturing, shipping, and buffer) and then calculates your inventory reorder point so you never run out of stock.

## Inputs

- **Order Processing Time** (days) — min 0, max 90 — Time from placing an order to it being confirmed/sent
- **Manufacturing / Procurement** (days) — min 0, max 365 — Time to produce or source the goods
- **Shipping / Transit Time** (days) — min 0, max 180 — Time from shipment to delivery
- **Buffer / Contingency** (days) — min 0, max 90 — Extra days for unexpected delays
- **Daily Demand (units)** — min 0, max 100000 — Average units sold or consumed per day
- **Safety Stock (units)** — min 0, max 100000 — Extra inventory buffer to prevent stockouts

## Outputs

- **Total Lead Time**
- **Total Lead Time**
- **Reorder Point**
- **Demand During Lead Time**

## Details

The formulas are:

  - Total Lead Time = Order Processing + Manufacturing + Shipping + Buffer

  - Reorder Point = (Daily Demand x Lead Time) + Safety Stock

Typical Lead Times by Source

  SourceTypical Lead Time
  Domestic manufacturer5-15 days
  Overseas (China, etc.)30-90 days
  Local distributor1-5 days
  Drop shipping3-14 days
  Custom/made-to-order14-60 days

Why Lead Time Matters

Understanding your lead time is critical for:

  - Inventory management: Know when to reorder before you run out

  - Customer expectations: Set accurate delivery timelines

  - Cash flow: Plan when payments will be due versus when revenue comes in

  - Production planning: Schedule work based on when materials will arrive

For example, if your lead time is 19 days, you sell 50 units/day, and you keep 100 units of safety stock, your reorder point is 1,050 units. When your inventory drops to that level, it's time to place a new order.

## Frequently Asked Questions

**Q: What is lead time in supply chain management?**

A: Lead time is the total time between placing an order and receiving the goods. It includes order processing, manufacturing or procurement, shipping/transit, and any buffer time for delays. Shorter lead times mean faster inventory replenishment and better customer service.

**Q: How do I calculate reorder point?**

A: Reorder point = (Daily Demand x Lead Time in Days) + Safety Stock. For example, if you sell 50 units/day with a 19-day lead time and keep 100 units of safety stock, your reorder point is 1,050 units. Place a new order when inventory hits that number.

**Q: How much safety stock should I keep?**

A: A common starting point is 1-2 weeks of average demand. So if you sell 50 units/day, that's 350-700 units of safety stock. Increase it if your supplier is unreliable, your demand is volatile, or stockouts are very costly. Decrease it if carrying costs are high.

**Q: What's the difference between lead time and cycle time?**

A: Lead time measures the total time from order to delivery (the customer's perspective). Cycle time measures how long it takes to complete one unit of work (the production perspective). Lead time includes waiting, processing, and shipping. Cycle time is just the active production portion.

**Q: How can I reduce lead time?**

A: Common strategies include: using domestic suppliers instead of overseas, keeping some pre-built inventory, using faster shipping methods, streamlining order processing with automation, building stronger supplier relationships for priority treatment, and reducing batch sizes in manufacturing.

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Source: https://vastcalc.com/calculators/everyday/lead-time
Category: Everyday Life
Last updated: 2026-04-08