Configuring Order Multiplicity for Product in 1C-Bitrix
Order multiplicity is the step of quantity change for a product in the cart. A buyer can add 6, 12, 18 units, but not 7 or 11. Implemented via the STEP_QUANTITY field in the b_catalog_product table.
Technical Foundation
In the b_catalog_product record for each product or trade offer are stored:
| Field | Purpose |
|---|---|
STEP_QUANTITY |
Quantity change step (multiplicity) |
MIN_QUANTITY |
Minimum quantity (see separate setting) |
MAX_QUANTITY |
Maximum quantity |
Multiplicity is applied when changing quantity in the cart. The bitrix:sale.basket.basket component, when a random number is entered, rounds it to the nearest multiple value in the larger direction.
Configuration via Admin Interface
Catalog → [select product] → "Quantity" tab:
Field "Quantity change step" — whole number. At STEP_QUANTITY = 6, a buyer can purchase 6, 12, 18... units. At value 0 or 1 — no restrictions.
For trade offers (variants), multiplicity is set separately for each offer, as different package sizes of one product can have different steps.
Bulk Configuration
Via CSV/XML import (Catalog → Product Import) column STEP_QUANTITY. For synchronization with 1C: in CommerceML format this property is transmitted as КратностьПродажи — ensure the mapping in the 1c.exchange module settings is correct.
Programmatic Setup
\Bitrix\Catalog\Model\Product::update($elementId, [
'STEP_QUANTITY' => 6,
'MIN_QUANTITY' => 6,
]);
It's recommended to set MIN_QUANTITY equal to STEP_QUANTITY or a multiple of it — otherwise situations are possible where the minimum quantity is not a multiple of the step.
Display in Cart
The standard cart component handles STEP_QUANTITY automatically: "+" and "−" buttons change the quantity with the specified step. In custom components or React/Vue frontends, this behavior must be implemented independently, reading STEP_QUANTITY from the catalog API response (CCatalogProduct::GetByID or REST API catalog.product.get).
Timelines
Setting multiplicity for a group of products — 2–3 hours, including bulk import and checking cart behavior.