Stock to Sales Ratio Calculator

For most e-commerce assortments, 1.0–2.0 is comfortable: enough cover to avoid stockouts without drowning in stock. The right number scales with lead time — a store restocking from overseas in eight weeks reasonably runs 2.0–2.5, while one with week-long domestic resupply can live near 1.0. Watch the trend as much as the level; a climbing ratio is the earliest over-buying alarm.

Either works, as long as both sides match. Retail-value inventory ÷ retail sales, or cost-value inventory ÷ COGS — never mix them, or your margin silently inflates or deflates the ratio by 30–50%. Most merchants find cost-to-COGS easiest because both numbers come straight from their accounting system without a markup assumption.

Same idea, different units and altitude. Stock-to-sales expresses cover in months of dollars and is usually computed store-wide or per category for buying budgets; weeks of supply is usually computed per SKU in units for reorder timing. A ratio of 1.5 is roughly 6.5 weeks of supply. Buyers plan open-to-buy with this ratio, then execute per SKU with weeks of supply.

One bad month moves the ratio mechanically because sales is the denominator; that alone is not a crisis. It becomes one if the level persists: two or three months above your normal band means the buying plan assumed demand that is not arriving. Respond by pausing reorders on the heaviest categories and pulling forward promotions — not by panic-liquidating after a single soft month.