Inventory glossary

What is In-stock rate?

In-stock rate is the percentage of time (or percentage of SKUs) a product is available for sale, rather than sitting out of stock.

A low in-stock rate means customers hit sold-out pages and buy elsewhere. For a small Shopify store, tracking this by SKU shows which products quietly go out of stock too often, even if total revenue looks fine on average.

Use it to spot patterns. If your best-selling candle is out of stock one week every month, you are losing sales you never see in your reports, because they just do not happen.

Formula

In-stock rate = (Days in stock / Total days) x 100

Example

A store sells a hoodie for 30 days. It is out of stock for 6 of those days. In-stock rate = (24 / 30) x 100 = 80 percent. If this happens every month, the store is missing sales on that hoodie one day out of five.

Common mistakes

  • Confusing in-stock rate with inventory accuracy, which measures whether system counts match physical counts, not availability.
  • Measuring only at a single point in time instead of over a full period, which hides short stockouts.
  • Ignoring variant-level gaps, so a product looks in stock overall while popular sizes or colors are actually sold out.

In-stock rate and SteadyShelf

SteadyShelf forecasts demand per variant and flags an order-by date per SKU, which helps you reorder before a stockout drags your in-stock rate down.

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

Related terms

Stockout · Out of stock rate · Fill rate · Service level · Lost sales

Full inventory glossary

FAQ

What counts as "in stock" for this rate?

Any period where a SKU or variant has quantity on hand greater than zero and is available for customers to buy.

Is a 100 percent in-stock rate always the goal?

No. Getting too close to 100 percent on every SKU usually means carrying more safety stock than needed, which ties up cash in slow movers.

Let SteadyShelf do this math for every SKU

Order-by dates per supplier, seasonal forecasts and draft POs for your Shopify store. $29/month after a 30-day free trial.

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