What is Fill rate?

A low fill rate means customers often hit out-of-stock items or get partial shipments, which costs sales and trust. Tracking fill rate by SKU or by supplier tells you where your stock levels or lead times are letting you down.

Use it as a health check, not a daily number. If a product's fill rate keeps dropping, raise its safety stock or order more often. If a supplier's fill rate is low because they ship late or short, factor that into your lead time and reorder timing.

Formula

Example

A candle store receives orders for 200 units of its signature candle in a month. It had 180 in stock and had to backorder 20. Fill rate = 180 / 200 x 100 = 90 percent.

Common mistakes

• Confusing fill rate with in-stock rate (whether an item shows as available), which is not the same thing.
• Measuring only at the order level and missing partial shipments where some lines are backordered.
• Ignoring fill rate by individual SKU and only looking at a blended store-wide number, which hides problem products.

Fill rate and SteadyShelf

SteadyShelf forecasts demand per variant and flags order-by dates, which helps you keep stock levels high enough to avoid the backorders that drag fill rate down.

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

Related terms

Stockout · Backorder · Service level · Safety stock · Lost sales

Full inventory glossary

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