Fill Rate

Fill rate shows how often inventory gaps force backorders, split shipments, or cancellations. Always state whether you measure units, lines, or orders, because the numbers differ.

Unit fill rate = units shipped on first shipment ÷ units ordered × 100

What is the difference between unit fill rate and order fill rate?

Unit fill rate counts the share of ordered units shipped complete on the first shipment. Order fill rate counts only orders where every unit shipped together, so it is always equal to or lower than unit fill rate.

• Backorder RateThe percentage of orders, or order lines, that contain at least one item that could not ship immediately because it was out of stock and was placed on backorder.
• Stockout RateThe percentage of active SKUs, or SKU-days, with zero available inventory during a period, sometimes measured instead as the share of orders affected.
• Safety StockExtra inventory held to cover variation in demand and supplier lead time.
• Split ShipmentAn order shipped in more than one package or from more than one location.