IDTRACE – Variation Quantity Rules for WooCommerce

IDTRACE – Variation Quantity Rules for WooCommerce lets you define independent quantity rules for each variation of a variable product: minimum quantity, quantity step (increment), and optional maximum quantity.

WooCommerce natively applies the same quantity constraints to all variations of a product. This plugin removes that limitation — each variation gets its own rules.

Who is this for?

Any WooCommerce store selling products where quantity depends on the variation:

• Labels & stationery — rolls of 500, 1000 or 2000 units with different minimums per reference
• Food & wholesale — packs of 6, 12 or 24 depending on the product format
• Hardware & industrial supplies — screws, bolts, fittings sold by the box of 50 or 100
• Printing & packaging — reams, cartons, palettes with format-specific batch sizes
• Cosmetics & pharmacy — consumables sold in boxes with regulated minimum quantities
• Textiles & haberdashery — spools or bobbins sold by the lot

In short: if your variations have different packaging constraints, this plugin handles them cleanly.

How it works

1. Open any variable product in WooCommerce admin
2. Expand a variation — three new fields appear below the price: Minimum quantity, Step, Maximum quantity (optional)
3. Save — done

On the product page, as soon as a customer selects a variation:

• The quantity field is automatically set to the minimum
• The min, step and max HTML attributes are updated accordingly
• Any invalid quantity triggers an error message before the customer can add to cart

Features

• Per-variation minimum quantity — independent value for each variation
• Per-variation step (increment) — customers can only order in multiples of the defined step, starting from the minimum
• Per-variation maximum quantity — optional upper limit
• Dynamic quantity field — updates instantly on variation selection (no page reload)
• Dual validation — JavaScript for immediate user feedback + PHP server-side validation that cannot be bypassed
• Cart update validation — rules are also enforced when quantities are edited directly in the cart
• Translatable error messages — uses wc_add_notice(), compatible with any language
• Clean uninstall — all plugin data is removed on uninstall; deactivation leaves data intact
• OOP architecture — clean, maintainable, extendable codebase

Step examples

Minimum = 4 / Step = 4 → customer can order: 4, 8, 12, 16, 20…
Minimum = 4 / Step = 1 → customer can order: 4, 5, 6, 7, 8…
Minimum = 1 / Step = 1 → standard WooCommerce behavior (no constraint)