What is Safety time?

Suppliers rarely deliver exactly on the day they promise. If you order based on the exact lead time with no cushion, a late shipment can leave you out of stock before the replacement arrives. Safety time builds in a buffer of days so you place the order earlier, rather than holding extra units on the shelf.

This matters most for suppliers with unreliable or long lead times, or for products where running out costs you real sales. You use it by adding a fixed number of days to the lead time when calculating your order-by date, rather than by stocking more units.

Formula

Example

A candle supplier quotes a 14 day lead time but has shipped as late as 18 days in the past few orders. The store owner adds 4 days of safety time, so orders are placed as if lead time were 18 days. If daily sales are 5 candles, the order-by point moves from 70 units of remaining stock (14 x 5) to 90 units (18 x 5).

Common mistakes

• Confusing safety time with safety stock and applying both without adjusting either, which creates too much buffer.
• Using the same safety time for every supplier regardless of how reliable each one actually is.
• Forgetting to revisit safety time when a supplier's performance improves or worsens.

Safety time and SteadyShelf

SteadyShelf calculates each SKU's order-by date from the supplier's lead time, so you can pad that lead time with your own safety time before approving a purchase order.

SteadyShelf is launching on the Shopify App Store. Join early access to get the install link first.

Related terms

Lead time · Safety stock · Reorder point · Supplier lead time variability · Lead time demand

Full inventory glossary

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