How Quantity Increment Calculation and Quantity Limit Work

The Quantity Increment (QI) function is a powerful tool to promote bulk sales and control inventory effectively. However, many merchants aren’t fully aware of how the rules operate: leading to missed opportunities to optimize store performance.

Product page with an increment of 5: the quantity box starts at 10 and a guide explains the allowed quantities

What your customers see on the storefront.

This article provides a detailed explanation of Quantity Increment Calculation and Quantity Limit, helping you apply them correctly to your Shopify store.

Setting Up Quantity Increment Rules

In the Quantity Increment Calculation section, you can select one of three rule types:

Variant Quantity
Product Quantity
Order Quantity

Let’s explore each with examples below 👇

Variant Quantity

Your customers must purchase a variant in multiples of the set quantity.

Example:
You set the Quantity Increment to 5 for products in the Necklace collection.

Product A has 2 variants: Black and White.
Customers must buy 5x Black A and/or 5x White A to check out.

🛒 On Cart Page:
Each variant must meet the increment requirement separately.

Cart with Revitalizing Youth Serum at a quantity of 5, the first allowed step of a Quantity Increment rule in packs of 5

Product Quantity

Your customers must buy a product’s total quantity (regardless of variant) in multiples of the increment number.

Example:

The Quantity Increment is 5 for the Necklace collection.
Product A’s total quantity (across all variants) must be 5, 10, 15… etc.

🛒 On Cart Page:
The total item count of Product A must satisfy the rule: color or variant doesn’t matter.

Order Quantity

Your customers’ total order quantity must be a multiple of the increment number.

Example:

The Quantity Increment is 5 for the Necklace collection.
On checkout, Product A = 6 items and Product B = 4 items → Total 10, which satisfies the rule.

🧾 On Checkout Page:
The system checks the total number of qualified products in the order.

💡 If the cart includes both Necklace collection products and other items, the rule applies only to products from the Necklace collection.

Example:
Rule: Order Quantity – 5

Total order = 11 items
Necklace collection = 10 items
✅ The order satisfies the rule because 10 is a multiple of 5.

Quantity Limit

The Quantity Limit feature lets you define the minimum and maximum quantity that customers can order: at the variant, product, or order level.

Example:
Rule: Necklace Collection – Order Quantity – 5

Minimum: 15
Maximum: 30

This means customers must buy at least 15 but no more than 30 items from the Necklace collection.

Scenario 1: Below Minimum

The total order quantity is under 15 → ❌ Checkout blocked
🛒 On Cart Page:
Customers will see a notice requiring more items.

Cart page: after clicking Checkout, a Warning pop-up says the buyer must choose at least 10 units of Gentle Skin Facial Cleanser

Scenario 2: Total Satisfied

Even if each product’s quantity is below 15, as long as the combined total of Necklace products meets the rule, ✅ checkout is allowed.
🧾 On Checkout Page:
The order passes validation successfully.

In Summary

Quantity Increment → Controls purchase steps (multiples).
Quantity Limit → Defines purchase boundaries (min/max).
Together, they give you precise control over order sizes, inventory flow, and wholesale pricing strategy.