Start with a stable group key
Many suppliers provide one row per clothing size or color. Add or identify a stable shared code for the product family. Do not rely exclusively on inconsistent display names.
Normalize units and values
Trim whitespace, make sizes consistent, remove currency symbols from prices, and verify inventory counts are non-negative integers. Give each item a unique variant SKU.
Generate the parent record
Create a variable parent with a shared product name, complete attribute option lists, a stable parent SKU and published status.
Generate the child records
Each variation should have its own SKU, regular price, matching Parent SKU and a single value for every mapped attribute.
Use a local converter and stage it
VariantFix beta performs this transform in your browser. Download the output and test it against the official WooCommerce importer on staging before changing your live store.