How to Set Up Low Stock Alerts in Shopify (Without Paying for an App): Part 1

Do you ever feel like ordering stock for your small business is a bit of a guessing game? Would you love a process that helps you feel more in control?

The good new is that Shopify has built-in, completely free tools that can help you manage your inventory more strategically (and automatically). One of the most powerful is Shopify Flow, a free automation app that can send you low stock alerts when it’s time to reorder.

I’m Katie, a small business Stock & Profit Specialist with over 20 years of retail experience. I also run my own Shopify store, so I know first-hand how overwhelming managing stock can feel  and how to simplify it. I now help other small business owners understand their numbers and use Shopify to make stock management easier.

Setting this up takes a little time at first, but your future self will thank you. Start small, get used to the process, and once you’re confident, you can build on it with more advanced checks and reporting (coming in Part 2!).

Step 1. Work Out Your Re-Order Point

Before Shopify can alert you that stock is low, you need to know what “low” means for your product.

You can work out when to reorder stock using this simple formula:

📱Re-order point = Average daily demand × Lead time (in days) + Safety stock

To find your average daily demand, take your total sales from a specific time period and divide it by the number of days in that period. For example, if you sell 150 candles in a month, divide that by 30 to get an average of 5 units per day.

Your lead time is how long it takes your supplier to deliver new stock after you place an order.

Your safety stock is a small buffer (typically 10–20% extra, or a few extra days’ or a week’s worth of sales) to protect against supplier delays or sudden spikes in demand.

Example:
If your average daily sales are 5 units and your lead time is 14 days, add a 3-day safety buffer (15 units).
→ 5 × 14 + 15 = 85 units
Your reorder point is 85 units.

Step 2. Add a Reorder Point Metafield

You’ll store each product variant’s reorder point inside Shopify so Flow can read it automatically. You can do this by using metafields.

💡 A metafield is just a custom field in Shopify where you can store extra information about a product — in this case, your reorder point.

To add one:

1. Go to Settings → Custom data → Variants → Add definition
2. Then fill in:
   1. Name: Re-order Point
   2. Namespace & key: inventory.reorder_point
   3. Type: Integer (whole number)
3. Click Save

Now, open each product variant and add its reorder point into this metafield.

💡 Tip: If you want to update metafields faster, you can use apps like Matrixify or Metafields Guru to bulk edit variant metafields and update them in one go.

Step 3. Install Shopify Flow

Shopify Flow is a free automation tool that lets you create simple “if this happens, then do that” rules in your store, no coding required.

To get started:

1. Go to the Shopify App Store, search for Shopify Flow, and install it.
2. In your Shopify admin, go to Apps → Shopify Flow.
3. Open the Templates section.
4. Choose "Get notified by email when product variant inventory is low."
5. Click Install and then edit the workflow:
   1. In the condition “Inventory quantity less than or equal to…”, click the recycle-style icon to change the variable
   2. Navigate to Product variant → Metafields → inventory.reorder_point.
   3. Do the same for the “Inventory quantity prior greater than…” condition.
   4. Update the Action step with your email address so alerts go to you.

You can also customise the email message or keep Shopify’s default template.

Want to get fancy?
You can make your flow more advanced, for example:

• Send a message to Slack to alert your team
• Update a Trello card
• Or even email your supplier directly when stock hits the reorder point

Step 4. Test Your Flow

Now it's set up, let's check that it's working.

To test your flow:

1. Pick one of your products.
2. Manually reduce its inventory to below the reorder point.
3. Wait for the alert email to arrive.

If it lands in your inbox, then congratulations! You’ve just automated a key part of your stock management.

💡 Alternative: One Reorder Point for a Product Group

If you’d rather not set individual reorder points for every product, you can keep things simple by using one Flow with a single reorder threshold, for example, 10 units.

In this version, instead of using the variant metafield as the variable, the Flow simply checks whether inventory is less than or equal to your chosen number.

To make sure this Flow only applies to the right products, you’ll need to add one extra condition:

• In your Flow, add a rule so it only runs for products with a specific tag. This tag could represent your reorder point (for example, reorder-10) or a product type like mugs or prints, whatever makes the most sense for how you group your products.
• Then, apply that tag to any products you want included in that group.

You’ll need to create a separate Flow for each threshold and tag you want to use.

This method works brilliantly for grouped products that sell at a similar rate, like greeting cards, art prints, or candles. It’s a great option if you’re just starting out or want a quick, easy way to automate Shopify low stock alerts without setting up metafields for every single variant.

Take the First Step Toward Better Stock Control

Setting up low-stock alerts in Shopify using Flow might feel a bit techy at first, but it’s one of the best ways to take control of your stock and stop ordering on a whim.

Once you’ve got it running, you’ll have peace of mind knowing you’ll never be caught short again and you didn’t need to pay for an app to do it.

Small changes like this can make a huge difference to your cash flow and confidence as a shop owner. The less time you spend worrying about stock, the more time you can spend creating, selling, and growing your business.

Just be sure to review your reorder points regularly, especially as your seasons (and therefore demand) change. Your ideal reorder point in summer might look very different to your winter one. I’ll walk you through a simple way to review and update your reorder points in Part 2.

If you’d love a hand setting up your Shopify Flow or building a smarter stock system that fits your business, get in touch, I’d love to help you make it simple.