A maximum cart quantity is useful when you want to limit how many total items a customer can buy in one order. This can help spread limited stock across more customers.
Before you start
- Decide the maximum total number of items allowed in one order.
- If you only want to limit one specific product, use Maximum product quantity instead.
Steps
1. Install Nex Validator
If Nex Validator is not installed yet, install it from the Shopify App Store and approve the required permissions. If it is already installed, skip to the next step.
2. Go to Simple Order Limit → Create Rule.
3. Give the rule a clear title, then make sure Enable/Disable Limit is turned on. If the rule is not enabled, it will not apply to customer orders.
4. Open the Cart tab and select Cart Max Quantity. Enter the maximum total number of items customers can have in their cart.
Example: if the maximum is 5, a cart with 5 items is allowed, while a cart with 6 items is blocked.
5. Add a clear message that tells customers the maximum allowed quantity, then save the rule. For example: “You can order a maximum of 5 items per order.”
Verify it worked
- Add more items than the maximum and go to checkout. Checkout should be blocked and your message should appear.
- Add exactly the maximum number of items. Checkout should continue normally.
Test the exact maximum too. If the maximum is 5, a cart with exactly 5 items should be allowed. A cart with 6 items should be blocked.
Common setups
| Goal | Example maximum |
|---|---|
| Flash sale orders | 2–4 items |
| Ticketed events | Your allowed quantity per order |
| Regulated products | The quantity your rules allow |
| Protecting a restock | 1–2 items |
Be careful not to set the maximum too low, because it may block valid larger orders. If retail and wholesale customers use the same store, Advanced rules can be used to apply the limit only in specific situations.