Role-based rules
Settings → Quantity & Pricing → Advanced rules → Store-wide role overrides lets each role, including Guest (not logged in), override min / max / step / default store-wide. The same table exists per product under the Quantity & Pricing tab. Typical setup:
| Role | Min | Step |
|---|---|---|
| Customer (retail) | 1 | 1 |
| Wholesale | 24 | 12 |
A user with several roles gets the most restrictive value per field.
Category rules
Edit a category under Products → Categories and fill the Quantity & Pricing fields plus a Priority. When a product sits in several categories, Settings → Advanced rules → Category conflict decides: Priority (highest-priority category wins per field) or Most restrictive (highest min, lowest max, largest step). Include parent categories also evaluates ancestors.
Cart-level rules
Limit the whole cart rather than a line: minimum / maximum items and minimum / maximum subtotal. Shoppers see the message in the cart and, if Block checkout is on, cannot proceed until the cart complies. Works in classic and block checkout.
Decimal quantities and units
Turn on Allow decimal quantities on a product to sell 1.5 kg or 2.25 m. Add a Unit label (kg, m) and it appears in the quantity hint, price table and, with Show unit label in cart, the cart. Step can be decimal too (0.25).