Quantity Constraints
How minimum, maximum, and step quantity rules work — and how quantities are counted in the cart.
Each rule can enforce up to three types of quantity constraint. You can use one, two, or all three on the same rule.
Minimum Quantity#
Sets the lowest number of units a customer can order. If the customer's cart total falls below this number, checkout is blocked.
Example: Minimum of 6 — a customer who adds 4 units sees:
Minimum order quantity for "Ceramic Mug" is 6. You have 4.
Leave this blank (or set to 0) to skip the minimum constraint on a rule.
Maximum Quantity#
Sets the highest number of units a customer can order in a single transaction. Useful for limiting bulk purchases or managing stock.
Example: Maximum of 24 — a customer who adds 30 units sees:
Maximum order quantity for "Ceramic Mug" is 24. You have 30.
Leave this blank (or set to 0) to skip the maximum constraint on a rule.
Step Quantity (Order Multiples)#
Requires the customer to order in exact multiples of a given number. Any quantity that isn't a clean multiple is rejected.
Example: Step of 6 — valid quantities are 6, 12, 18, 24… A customer who adds 7 or 10 sees:
"Ceramic Mug" must be ordered in multiples of 6. The nearest valid quantity is 12.
The error message helpfully suggests the next valid quantity above what the customer has.
Combining step with minimum#
Minimum and step quantity work together. Setting a minimum of 12 and a step of 6 means a customer must order at least 12 units and in multiples of 6 — so 12, 18, 24, and so on.
Step quantity is ideal for products sold in packs, pairs, or cases where partial-pack orders don't make sense.
How Quantities Are Counted#
If a customer adds the same product to their cart more than once — for example, by adding two variants separately, or by adding the same product via different add-to-cart actions — the quantities are combined before being checked against the rule.
Example: A customer adds 4 units of "Small" and 4 units of "Large" for the same product. A minimum of 6 on that product checks a combined total of 8 — so they pass.
Aggregation applies per-product for product rules. Variant rules only count the quantity for that specific variant, not the whole product.
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