Units of measure (UOM) and pack sizes

A purchase order rarely asks for 36 of something. It asks for 3 cases, and expects you to know that a case is 12.

Shopify does not know that. A variant is sold in single units, so a draft order has to carry 36. Units of measure (UOM) are how PO Autopilot gets from one to the other.

The arithmetic

The buyer orders 3 CASE. One case is 12 EACH. The Shopify draft order carries 36 of the variant.

The number you supply is the middle one: how many Shopify units are in one of the buyer’s units. Everything else follows from it.

When you are asked

If a line arrives in a unit with no known conversion, the line raises Define the unit conversion, and the field is labelled Shopify units per followed by the unit — Shopify units per CASE. The unit is shown normalised there, so a document that said CS still reads CASE.

You are only asked once per buyer, code and unit. After that the conversion is applied automatically.

Singles are not a question

A line ordered in eaches needs no conversion — one is one — so nothing is asked. The question appears for cases, cartons, boxes, dozens and anything else that means more than one.

Different spellings, same unit

Buyers write the same unit many ways. CS, CASE and CTN are understood as the same unit, so a conversion taught from a document that says CS applies to the next one that says CASE.

The conversion belongs to the buyer, the code and the unit

A conversion is stored with the product mapping, which means it is specific to three things at once: the company location, the buyer’s item code, and the unit.

This has a consequence worth understanding. A case decision is never applied to an order in singles. If the same buyer orders ACME-WAX-CS as 2 CS one week and 6 EA the next, the second order asks its own question rather than multiplying by six.

That is deliberate. The quantities mean different things, and inheriting the case multiplier would order six times too many — silently, on a real order.

Different buyers, different cases

One buyer’s case of a product can be twelve while another’s is six. Because the conversion is held per company location, both are correct at the same time.

Getting it wrong

The conversion is not checked against anything — nothing in Shopify knows your pack sizes, so nothing can confirm it. A 12 typed as 1 produces a draft for 3 units instead of 36.

The totals are the guard. The order is priced through Shopify as part of creating the draft, and a wrong conversion shows up plainly in what it comes back with. If you find a mistake later, fix the mapping under Mappings so it does not repeat — see Create and manage UOM mappings.