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).