Inventory glossary
What is Size run?
A size run is the set of sizes a store orders for one style, usually stated as how many units of each size make up one case or one order, like 1-2-2-1 for small-medium-large-extra large.
A size run matters because it controls how much of each size lands on your shelf, not just how many units total. If your size run does not match how customers actually buy, you end up with too many extra larges and not enough mediums, even though your total inventory count looks fine.
To use it well, check sell-through by size each season and adjust the ratio in your next order. If mediums sell out first every time, shift the run so mediums make up a bigger share of each case, instead of ordering the same split out of habit.
Example
A t-shirt store orders a style in a case pack of 12 with a size run of 2-4-4-2 across small, medium, large, extra large. If they order 5 cases, they get 10 small, 20 medium, 20 large, and 10 extra large, for 60 units total.
Common mistakes
- Using the same size run for every style even when past sales show a different split by size.
- Ignoring sell-through by size and only tracking total units sold for the style.
- Forcing order quantities into full cases without checking if the resulting size run creates leftover sizes.
Size run and SteadyShelf
SteadyShelf forecasts sales and suggests order quantities per variant, so you can see demand by size before deciding on your size run and rounding to case packs.
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Related terms
Size curve · Case pack · Variant · SKU · Assortment planning
FAQ
Is a size run the same as a size curve?
They are closely related. A size curve usually refers to the sales distribution across sizes over time, while a size run is the fixed ratio you order in, often tied to a case pack. Stores often set their size run based on the size curve.
Can a size run change between orders?
Yes. A size run should be reviewed each time you reorder, based on which sizes are selling out and which are left over, rather than locked in forever.
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