Lead Time Calculator (Order to Shelf)

Add up every stage between placing an order and having stock ready to sell. Enter your own numbers, no account needed.

By Tibeau De Grauwe, FounderUpdated September 2026

  • 25 products free
  • No credit card
  • 10-min setup

Lead time is the time between deciding to reorder and having the goods received, checked and ready to sell. Suppliers often quote only their own production or shipping time, which understates what your stock actually experiences (for example, a supplier may say "5 days" while your real lead time is 12).

Enter the days for each stage: internal order processing, the supplier’s production or picking time, transit, and your own receiving and put-away. Use averages from recent orders, and check the slowest recent order as well, because that one drives your safety stock.

Once you have the total, feed it into the reorder point calculator. A reorder point that ignores receiving and put-away days is a common cause of items arriving physically but still being unavailable to sell.

Lead Time Calculator

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days
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Total lead time

12 days

About 1.7 weeks

How the calculation works

Total lead time = order processing + supplier production + transit + receiving and put-away.

Example: 1 + 5 + 4 + 2 = 12 days, or about 1.7 weeks. If demand is 20 units a day, you sell roughly 240 units while the order is on its way, which is the number your reorder point has to cover.

The figure is an average. If your supplier is sometimes late, plan around the slowest realistic case, or add a safety stock buffer on top.

See also: Reorder point calculator, Glossary: lead time, Stock cover calculator.

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Copy this code into your page. The calculator runs in the visitor's browser and includes a link back to StockFlow.

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Frequently asked questions

How do you calculate lead time?
Add the time of each stage between deciding to reorder and having stock ready to sell: order processing, supplier production or picking, transit, and receiving and put-away.
What is the difference between lead time and transit time?
Transit time is only the shipping leg. Lead time covers the whole cycle, including order processing, the supplier’s own production time and your receiving and put-away.
How does lead time affect the reorder point?
Reorder point = daily demand × lead time + safety stock, so a longer or less reliable lead time means you have to reorder earlier or hold more buffer.
Does this calculator store my data?
No. The calculation runs entirely in your browser; nothing is sent to or stored on a server.

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