Use discount conditions to control Shopify discount combinations at checkout. You can block a cart when it has a discount, or combine a discount check with other conditions to block only certain carts.
Shopify's own discount combination settings decide which discounts can stack. BlockCart adds a check on top: it can stop checkout when a discount shows up on a cart you don't want discounted.
What each discount condition checks
All three fields appear under Discount when you add a condition. They are available with every Rule input choice.
| Condition | What it checks | Available comparisons |
| ---------------------- | --------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- |
| Global discount | The sum of discount amounts allocated to the cart, including shipping discounts. A cart with no allocated discount has a value of zero. | is greater than, is greater than or equal to, is less than, is equal to |
| Order discount | Whether the cart has a nonzero discount application aimed at line items. A shipping-only discount does not match. | is or is not, with true or false |
| Line item discount | Whether any cart line has a discount amount greater than zero. | is or is not, with true or false |
Global discount checks an amount, while Order discount and Line item discount check whether a discount exists. The two yes-or-no checks can both match the same cart. Neither checks a discount code's text or identifies which product received a particular discount.
If you set a Global discount amount, BlockCart compares your number with the amount in the customer's Shopify checkout currency. It does not convert currencies. For different thresholds by currency, use Cart currency in a separate condition group for each currency. See Cart conditions: subtotal, total, quantity, currency.
Block discounts on certain carts
For example, to stop checkout when a selected product is in the cart and an order discount is applied, put Cart contains and Order discount is true in the same condition group. Conditions in one group must both match before the rule shows your error message. See Combine conditions with AND and OR groups for the grouping steps.
If your goal is to use a Shopify discount code to exclude products, remember that this rule checks the cart and the presence of a discount. It does not verify that the selected product itself was discounted, or distinguish a code from an automatic discount. See Stop discount codes on certain products for a worked example.