Fractional Stock
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The “Fractional Stock” add-on helps sell products in fractional or step-based quantities: by weight, volume, length, package, or other units of measure.
What it is for
For grocery, building materials, textile, liquid, and similar stores where customers need to choose an exact quantity with a required step instead of only whole pieces.
The add-on lets the administrator define a product unit of measure, quantity step, minimum quantity, and maximum quantity, while customers see and choose the correct quantity on the storefront, in the cart, and during checkout.
Key features
- selling products with fractional quantities, such as 0.5 kg, 1.25 l, or 2.5 m;
- setting a unit of measure per product or using a global default unit;
- setting a quantity step, minimum value, and maximum value;
- correct quantity rounding when a product is added to the cart or an order is changed;
- showing the unit of measure near the quantity on the storefront, in the cart, and at checkout;
- working with bulk product update;
- compatibility with the updated checkout product list in the “Improved checkout” add-on.
How it works
The administrator enables fractional stock globally or for selected products, then sets the unit of measure and quantity rules. Customers enter the quantity manually or change it with buttons, and the add-on adjusts the value to the allowed step and checks the limits.
On the checkout page the quantity can be changed without returning to the cart. When used together with the “Improved checkout” add-on, the product list keeps units of measure, the old price, and correct totals updates. The main settings are available in the add-on card, product-specific settings are in the product card, and bulk update is available for groups of products.
Have questions about the add-on?
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Instructions for the “Fractional Stock” add-on
What the add-on does
The add-on lets you sell products in fractional or step-based quantities: by weight, volume, length, and other units of measure. A unit of measure, quantity step, minimum quantity, and maximum quantity are set per product, and customers see and choose the correct quantity on the storefront, in the cart, and at checkout.
Where to find the add-on
The settings are available in the Fractional Stock add-on card under Administration → Add-ons → Manage add-ons. Product-specific settings are in the product card, in the “MS: Fractional Stock” section. Bulk setup is available under Administration → Products → Bulk update.
How to configure it
- Open the “Fractional Stock” add-on card.
- Enable “Use fractional stock”.
- Set the default unit of measure — for example pcs., kg, or l.
- Save the changes.
Important: the add-on conflicts with csc_fractional_stock — both cannot be used at the same time. The add-on is intended for the MULTIVENDOR and ULTIMATE editions.
Product setup
Open the product card and find the “MS: Fractional Stock” section. It contains the fractional stock switch, the unit of measure, the quantity step, and the minimum and maximum quantity.
Bulk update
Under Administration → Products → Bulk update select the products and set the fractional stock parameters for the whole group at once.
How it works on the storefront
On a product page with fractional stock enabled, the customer enters a fractional quantity (for example, 1.5 or 2.3). The value is rounded to the configured step and checked against the minimum and maximum limits. In the cart and at checkout the quantity is shown together with its unit of measure.
If the “Improved checkout” add-on is used, the customer can change the fractional quantity directly on the checkout page with buttons or manual input, without returning to the cart.
Examples
- food: unit “kg”, step 0.1 — an order of 1.5 kg or 2.3 kg;
- liquids: unit “l”, step 0.1 — an order of 0.5 l or 1.2 l;
- packages: unit “pkg”, step 0.5 — an order of 1.5 packages.
How to check the result
- Enable fractional stock and set the default unit of measure.
- Set up a test product: unit of measure, step, minimum, and maximum.
- Open the product page on the storefront and enter a fractional quantity — the value must be rounded to the step.
- Check the limits: a quantity below the minimum and above the maximum must not be accepted.
- Add the product to the cart and check that the quantity is shown with its unit of measure.
- Go to checkout and, if the “Improved checkout” add-on is used, change the quantity directly on the page.
Typical problems
- Fractional quantities do not work. Check that the add-on is active, the global option is enabled, and fractional stock is enabled for the product.
- The quantity is not rounded. Check the quantity step in the product settings.
- The limits do not work. Check the minimum and maximum quantity in the product settings.
Changelog
v1.3.3 from 29.10.2026
[*] Updated the add-on description and instructions; added localized materials and the logo.
v1.3.2
[*] Updated the add-on template.
v1.3.1 from 2026-05-22
[+] Added compatibility with the “Improved checkout” add-on: products with fractional stock are displayed and edited correctly on the checkout page.
[+] Quantity updates at checkout now support plus and minus buttons, manual input, and recalculation without a page reload.
[*] Improved the product list display at checkout: units of measure, old price, and responsive layout look correct.
[!] Improved the visual display of the out-of-stock status in the UniTheme2 theme.
[!] Fixed double quantity update triggers when used together with the “Improved checkout” add-on.
[!] Fixed element overlap in the delivery block after updating products at checkout.
[!] Improved the display of the price per unit on the storefront.
v1.3.0 from 2026-03-19
[*] Changed the product display template on the checkout page for the UniTheme2 theme.
[*] Aligned the code style with the CS-Cart standard.
[!] Fixed the product quantity display in the cart so that it matches the product card.
[!] Fixed a migration error of the fractional stock settings during an add-on update.
[!] Removed the cart request dependency on unused CommerceML data.
v1.2.0 from 2026-02-23
[+] Added unit of measure and quantity step data to the cart frontend API.
[*] Updated the add-on template.
[!] Fixed adding a general product from the product card to favorites so that the product is not added twice.
v1.1.0 from 2025-09-08
[+] Added support for fractional product quantities in the mobile app cart.
[*] Changed the algorithm for determining the minimum product quantity per order.
[*] Standardized the add-on.
[!] Fixed an error when removing products from the cart.
v1.0.0 from 2025-04-25
[+] First release of the add-on.
Legend:
[+] Added
[-] Removed
[*] Changed
[!] Bug fixed
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