Stacking discounts

Control which discounts can apply together — across discount classes and on the same cart line

By default, Shopify allows one discount per class at checkout: one product discount, one order discount, and one shipping discount. Stacking lets multiple discounts apply to the same cart in two dimensions:

• Across classes — combine a product discount with an order discount, a shipping discount, or all three.
• On the same cart line — apply two product discounts to the same line item (e.g. seasonal sale + loyalty perk).

Both dimensions are configured in the Combinations card on the discount editor.

Discount classes

Every discount belongs to one or more classes:

Class	What it discounts
Product	Specific cart line items (e.g. 20% off T-shirts)
Order	The whole order subtotal (e.g. $10 off any order over$100)
Shipping	Shipping rates (e.g. free shipping on orders over $75)

A discount of class X can combine with discounts of any class — including its own — except shipping. Two shipping discounts can never apply to the same shipment.

Combining across classes

In the Combinations card, check the classes this discount should combine with. The other discount also has to opt in: combining is only allowed when both discounts list each other’s class.

Combinations are mutual. If you add a 20% off Order discount and a Free Shipping discount, both must check the other’s class for them to apply together.

Combining on the same cart line

This feature is only available on Shopify Plus plans.

By default, only one product discount applies to any given cart line. If a customer has both “20% off T-shirts” and “Buy 2, get 1 free” eligible for the same shirt, only the better-value discount wins.

To stack two product discounts on the same line, both discounts must:

1. Be tagged with one or more shared tag (e.g. SEASONAL).
2. Opt in to combining on that tag in the Combinations card.

When this discount and another product discount share a tag in their cart-line lists, both apply to the same line.

Example — seasonal sale + loyalty bonus

You’re running a seasonal 15% off sale on outerwear and want to layer a 5% loyalty bonus on top for VIP customers.

Discount	Tags	Cart-line combines with
Seasonal sale (15% off jackets)	SEASONAL, LOYALTY	LOYALTY
VIP loyalty bonus (5% off everything for VIPs)	LOYALTY	SEASONAL

Both discounts list LOYALTY (or SEASONAL) on the other’s tags, so they stack. A VIP customer who buys a jacket gets 15% + 5% on the same line.

How tags work in cart-line stacking

• Tags are set on the discount itself (in the Tags card in the editor).
• The cart-line list in Combinations says “I’ll stack on a line with another product discount that has any of these tags.”
• The match is bidirectional — both discounts must list a tag the other has.
• Up to 5 tags per cart-line list.

Order of application

When multiple product discounts stack on the same cart line, Shopify applies them in a fixed order:

1. Percentage discounts before fixed-amount discounts.
2. Within each group, highest economic value first — the discount worth the most applies before the discount worth less.

This ordering is Shopify checkout behavior we’ve observed. It isn’t currently documented by Shopify, and it’s not something Discount Kit — or any app — can control or configure. It may change without notice.

Stacking and Discount Kit Live

Discount Kit Live writes scalar metafields like max_reward_percent that reflect the best individual discount for a product. Stacked discounts are not pre-computed in Live’s metafields — the actual stacked total only resolves at checkout.

If your storefront badging or pricing copy depends on the post-stack total, render it from the cart object at runtime rather than from the product-level Live metafields.