Order Quantity Increments: Avoiding Rounding Errors in the Cart
Ever faced a situation where a wholesale customer adds 23 units of a product to the cart, but the packaging is only in packs of 12? The result: rounding errors, an unhappy client, and a lost deal. For wholesale catalogs with packaging in boxes, crates, or pallets, order quantity increments are a must. We eliminate such issues by configuring increments at the catalog and cart level. Our engineers have 8+ years of experience and dozens of projects, ensuring a hassle-free integration. Contact us to get a consultation for your project.
Why Quantity Increments Matter
A quantity increment is the step by which the product amount changes in the cart. It is critical for goods with fixed packaging: alcohol in 6-bottle cases, bulk products in 25 kg bags. Without proper increments, the system cannot calculate the order or will round the quantity incorrectly, leading to cash gaps. Online stores with wholesale functionality lose customer loyalty due to the inability to order the required amount. Proper increment configuration builds trust and reduces cart abandonment. Our clients save up to 70% of time managing increments after automation.
How STEP_QUANTITY Works in Bitrix
The STEP_QUANTITY field is stored in the b_catalog_product table. If it is 0 or 1, the increment is disabled. The standard cart component bitrix:sale.basket.basket automatically rounds the entered quantity up to the nearest multiple. For example, with STEP_QUANTITY=6 and input 10, the cart shows 12. The table below presents all three quantity control fields:
| Field | Purpose |
|---|---|
STEP_QUANTITY |
Quantity change step (increment) |
MIN_QUANTITY |
Minimum quantity |
MAX_QUANTITY |
Maximum quantity |
Importing via CSV is 10 times faster than manual configuration: manual editing of each product takes up to 5 minutes, while a bulk import of 1000 products takes about an hour. Programmatic update via API is even faster — roughly 30 minutes.
How We Configure Increments: A Case from Our Practice
Recently, we worked with a client — a power tool distributor. Their catalog contains 1200 products, most with packaging in packs of 10. Standard configuration via the admin panel would take weeks. We used bulk CSV import and programmatic update:
\Bitrix\Catalog\Model\Product::update($elementId, [ 'STEP_QUANTITY' => 10, 'MIN_QUANTITY' => 10, ]); Additionally, we configured mapping in CommerceML (the КратностьПродажи property) so that the increment updates automatically during 1C synchronization. The entire project took 3 hours, including testing cart behavior on 100 test orders. According to the official Bitrix documentation, this is the standard approach.
What's Included in the Work
- Audit of the current quantity scheme (STEP_QUANTITY, MIN_QUANTITY, MAX_QUANTITY) in the database.
- Configuration of increments for selected products/groups: via admin panel, import, or programmatically.
- Harmonization with minimum quantity (prevent non-multiple values).
- Testing cart functionality (standard and custom) for rounding issues.
- Integration with 1C (CommerceML) for automatic increment synchronization.
- Documentation for maintenance and training for managers.
Process: From Analysis to Deployment
- Analysis — collect requirements: which products, what packaging, whether SKUs are used.
- Design — choose the configuration method: bulk import, script, or manual editing.
- Implementation — update
b_catalog_productvia import or API, verify correctness. - Testing — create test orders with different increments, check rounding in cart and checkout.
- Deployment — apply settings to production, monitor logs.
When Custom Development Is Needed
If you use custom cart components (React/Vue) or a non-standard checkout, increment behavior must be implemented manually. We connect to the catalog REST API (method catalog.product.get) and add rounding logic on the frontend. Comparison: on a standard component, configuration takes 2–3 hours; on a custom one, it takes from 8 hours (4 times longer). The choice depends on your site's architecture. Order increment configuration today — get a free engineer consultation.
Timeline and Cost
Timeline — from 2 hours (for a group of products via import) to 2 days (with 1C integration and custom cart). Cost is calculated individually after analyzing the scope of work. We guarantee no rounding errors after configuration and offer post-release support for 30 days. Contact us to avoid rounding errors — we will send a preliminary estimate within 24 hours.