Safety Stock

What Is Safety Stock?

Safety stock is the cushion of inventory a brand holds beyond what it expects to sell during the time it takes to restock. It is there for the moments when sales run hotter than forecast or a supplier shipment shows up late.

Without safety stock, any surprise in demand or supply turns directly into a stockout.

How It Works

The amount of safety stock depends on how variable your demand is, how reliable your suppliers are and how important it is to never run out. A simple starting formula multiplies a buffer number of days by average daily sales.

For example, if a protein powder sells 30 units a day and the supplier is sometimes up to ten days late, a brand might keep 300 units of safety stock. More advanced methods use the standard deviation of demand and lead time to set a buffer based on a target service level.

Safety stock is then built into the reorder point. A brand reorders when stock falls to the expected lead time demand plus the safety stock, so the buffer is still there when the new shipment arrives.

• Higher for bestsellers and unreliable suppliers.
• Lower for slow movers and short lead times.
• Reviewed regularly as demand changes.

Why It Matters for Ecommerce Brands

Running out of a bestseller costs sales, ad efficiency and customer loyalty. Safety stock protects against that. At the same time, too much safety stock ties up cash and adds storage fees, so the buffer should be set thoughtfully and reviewed as sales patterns change.

Seasonal events, product launches and influencer campaigns are common reasons to raise safety stock temporarily, then lower it once demand settles.