One of the most frustrating challenges for Shopify store owners is the inability to prevent discount codes from being applied to products that are already on sale using the compare-at-price functionality. This issue can significantly affect profit margins, create confusion for customers, and disrupt a store’s overall pricing strategy.

If you’ve ever found yourself in a situation where customers could apply a discount code on top of an already discounted product, leading to unintended double discounts, you’re not alone. Many Shopify merchants struggle with this problem, and Shopify’s native functionality does not offer an easy fix.

In this guide, we’ll explore why Shopify allows discount stacking, what workarounds exist, and the most effective long-term solution - specialized apps, like Alpha Sale to prevent discount stacking on sale items. By the end of this article, you’ll have a clear strategy to stop unnecessary revenue loss while maintaining an effective discount system in your Shopify store.

Why Does Shopify Allow Discount Stacking?

To understand the issue, let’s first break down Shopify’s built-in discount system. Shopify provides three main types of discounts:

• Product Discounts – Applied to specific products or collections.

• Order Discounts – Applied to the entire cart.

• Shipping Discounts – Reduce or remove shipping fees.

If you’re using these discounts separately, there’s no problem – Shopify doesn’t allow multiple discounts of the same type to be applied at once. However, the problem begins when you want to show discounts directly on product pages.

Shopify does not allow native discounts to be displayed on product pages, which forces many store owners to use the compare-at-price feature. This setup involves moving the original price into the compare-at-price field while setting the new discounted price as the actual selling price.

However, while Shopify officially recommends this method for flash sales and promotions, it completely ignores the compare-at-price field when applying additional discount codes. 

Instead, Shopify always applies discounts to the final selling price, not the original compare-at price. This results in customers receiving additional discounts on already reduced items, also known as discount stacking.

Why is this a problem?

For Shopify merchants, discount stacking can lead to several issues:

• Profit erosion: Applying multiple discounts to already-reduced items can significantly impact profit margins and, in some cases, lead to financial losses.

• Customer confusion: Customers may receive a final price different from what they expected or what was advertised to them via email or other marketing channels.

• Unintentional pricing mistakes: Store owners may not realize the issue until multiple orders have been processed with stacked discounts, resulting in unintended revenue loss.

Shopify’s lack of a built-in solution has left many merchants searching for workarounds to prevent this from happening.

Workarounds to Prevent Discount Stacking

If you search Shopify forums or Reddit, you’ll find countless discussions about this issue. Below are three commonly suggested workarounds. While they help mitigate the problem, they each come with trade-offs.

1. Use default Shopify discounts instead of compare-at prices

One option is to stop using the compare-at-price feature altogether and instead use Shopify’s automatic discounts or discount codes. This means you won’t have a visible strike-through discount on product pages, but rather, customers will see the discount applied at checkout.

Pros:

• Prevents customers from applying multiple discount codes.

• Uses Shopify’s native discount system, ensuring smooth compatibility.

Cons:

• Customers can’t see the discounted price upfront, which can lower conversion rates.

• You need to rely on announcement banners or other marketing tools to communicate promotions.

2. Create a collection for full-price items

Another workaround is creating a smart collection that includes only products that do not have a compare-at price. This collection updates automatically - whenever a product goes on sale (i.e., when a compare-at price is added), it is removed from the collection. You can then set your discount codes to apply only to this collection, ensuring sale items remain ineligible.

Pros:

• Automates part of the discount process.

• Ensures discount codes only apply to full-price items.

Cons:

• Limits flexibility - you can’t choose to apply discount codes only to a list of specific products or vendors, you always need to stick to a collection-based setup.

• Requires careful setup and management.

3. Manually adjust discount rules

Some merchants manually adjust discount rules every time a sale is launched. For example, if you put a new product on sale, you manually update your discount settings to exclude that product from the targets.

Pros:

• Offers precise control over which products receive discounts.

Cons:

• Time-consuming and error-prone, especially for larger stores.

• Not scalable for merchants who run frequent sales.

While these workarounds provide temporary fixes, the best way to completely eliminate discount stacking is by using a third-party app that automates the process.

Automated Solution: Use the Alpha Sale App to Prevent Discount Stacking

Since Shopify does not offer a built-in way to block discount stacking, using an app is the most effective and scalable solution. 

Alpha Sale, for example, allows you to create discount codes - just like Shopify’s native ones - but with added control. You can choose to either automatically exclude products with a compare-at price or ensure that only the largest discount applies, preventing unintended double discounts.

1. Excluding sale products entirely

If you want to ensure that discounted products never receive additional promotions, Alpha Sale allows you to automatically exclude products with a compare-at price from discount codes.

How It Works:

When setting up discounts, simply enable the “Exclude products already on sale” option.

This prevents any additional discount from being applied to items that are already reduced.

2. Applying discount codes based on the compare-at price

If you don’t want products to be completely excluded but want to avoid double-discounting, Alpha Sale allows you to apply discount codes to the original compare-at price instead of the current sale price.

How It Works:

If an item is on sale, the discount will be calculated from the original compare-at price, not the already reduced price.

This ensures that only the largest discount applies - either the sale price or the coupon, whichever is greater.

Example Scenarios:

With this setup, customers never receive stacked discounts, and you retain control over the pricing structure.

Additional Features for Greater Flexibility

Beyond preventing discount stacking, Alpha Sale offers extra flexibility to fine-tune your promotions:

• Flexible targeting – Apply discounts to specific vendors, product tags, or the entire store for faster campaign setup.

• Advanced discount logic (AND/OR groups) – For example, you can target products in a specific collection only if they also have a certain tag.

• Customer segmentation – Exclude or include customers based on tags for personalized promotions.

• Limit total discount amount – Ensure that your total discount doesn’t exceed a reasonable amount.

Whatever settings you choose, Alpha Sale gives you full control over your discount strategy while ensuring you don’t lose revenue due to unintentional stacking.

Conclusion

Preventing discount codes from applying to sale items is a critical feature that Shopify currently lacks. While workarounds exist, the most effective and scalable solution is to use third-party apps designed to handle discount exclusions automatically. By leveraging tools like Alpha Sale, Shopify merchants can safeguard their revenue, streamline sales promotions, and maintain better control over their pricing strategy.

For store owners who frequently run promotions, investing in the right discount management tool can be a game-changer.

Check out Taranker’s guide for more expert tips related to discount strategy!