Warehouse & logistics
Unit of Measure (UoM)
By the Supply Chain Manager team · Updated October 16, 2026
Unit of measure (UoM) is the unit an item is counted in, such as each, box, case or pallet, plus the conversions between them.
Distributors often buy in one unit and sell in another: buy by the case of 12, sell by the each. Every stock figure, forecast and purchase order has to use the right unit, or quantities are wrong by a factor of 12.
A good rule is to pick one base unit per SKU, usually the smallest unit you sell, and store every other unit as a conversion to it. Purchase orders, receipts, sales and forecasts can then use whatever unit is natural, while every stock calculation runs in the same base unit.
Unit of measure example
Illustrative: a supplier's price list is per case of 24, but your system records stock in eaches. A reorder of '50' sent without the unit could mean 50 eaches or 1,200, which is the kind of error that creates a year of overstock in one order.
Why unit of measure matters for distributors
UoM errors are one of the most common causes of bad imports and wildly wrong purchase orders. Storing one base unit and explicit conversions avoids them.
Common unit of measure mistakes
- Mixing units in the same column of an import file.
- Changing a supplier's pack size without updating the conversion.
Examples on this page use made-up round numbers to show the calculation. They are not benchmarks or results from real businesses.