Shopify Low Stock Alerts: How to Set Reorder Points and Never Stock Out

A stockout is not bad luck — it is a math problem. You ran out because you did not know when to order. This guide explains how to calculate the right reorder point for every Shopify SKU, set automated low stock alerts that fire at exactly the right moment, and convert those alerts into purchase orders in seconds.

Why Stockouts Destroy Shopify Revenue (With Numbers)

When a customer lands on a product page and sees "Out of Stock," most of them leave. They do not bookmark the page and come back when you restock — they buy from a competitor. IHL Group research found that 43% of out-of-stock shoppers simply buy elsewhere. For a merchant doing $50k/month in revenue, that is roughly $21,500 in lost sales every month you allow stockouts to persist.

The impact compounds. Stockouts damage your Shopify store's conversion rate, which affects how Shopify's algorithm surfaces your products in search. If you run ads, your cost per acquisition increases because traffic lands on unavailable products. And repeat customers — your most valuable segment — learn not to trust your availability, eroding lifetime value.

Most Shopify merchants who stock out do so not because inventory management is hard, but because they never set a proper reorder point. They rely on gut feel — "it looks low, better order" — or on Shopify's basic low-stock email that fires at an arbitrary threshold with no link to supplier lead time. By the time the alert fires, it is already too late.

What Shopify's Native Stock Alerts Actually Do (and Don't Do)

Shopify does have a built-in low stock notification. You can go into any product variant in Shopify Admin, scroll down to the inventory section, and enter a number in the "Low stock threshold" field. When stock falls to or below that number, Shopify sends an email to your store email address.

That is where it ends. Shopify's native alert system has four significant limitations:

• No formula. Shopify does not help you calculate what the threshold should be. It accepts whatever number you type. Most merchants enter 5 or 10 as a round number with no basis in lead time or sales velocity.
• No supplier awareness. The alert is not connected to any supplier record. It does not know that this product comes from a supplier who takes 21 days to deliver, which means you need to order sooner than a product from a 5-day domestic supplier.
• No path to action. The alert email says "your stock is low." That is it. You then have to manually find your supplier's contact, look up your last order, figure out what to order, and email them. There is no purchase order link.
• No dashboard view. Shopify has no single screen where you can see all your low-stock products sorted by urgency. You get individual emails, one per variant, with no prioritization.

How to Calculate the Right Reorder Point (The Formula)

A reorder point is the stock level at which you need to place a new order so that new stock arrives before you run out. It is a function of two variables: how fast you sell (demand) and how long it takes to get more (lead time). The formula is:

A worked example

Suppose you sell a product at an average of 12 units per day (360 units over the last 30 days). Your supplier takes 14 days to deliver. During peak periods you sometimes sell 18 units a day, and your supplier has been as slow as 18 days.

• Base demand during lead time: 12 × 14 = 168 units
• Safety stock: (18 − 12) × 18 = 108 units
• Reorder point: 168 + 108 = 276 units

When your stock drops to 276 units, place the order. If everything goes to plan you will receive stock with exactly 168 units remaining. The safety stock of 108 units is your buffer if sales spike or the supplier runs late.

What safety stock actually covers

Safety stock is often misunderstood as "extra inventory you waste money on." It is not — it is insurance against two specific risks:

• Demand variability: sales higher than the average during the lead time window.
• Supply variability: your supplier delivering later than their stated lead time.

If your supplier is perfectly consistent and your sales are flat, you theoretically need zero safety stock. In practice, every supplier occasionally runs late and every product occasionally spikes. The size of your safety stock should reflect how variable your specific supplier and product are — not a round number you picked arbitrarily.

Seasonal products require recalculation

If you sell seasonal goods, your historical 30-day velocity can be dangerously wrong. A product that sells 5 units a day in January might sell 40 units a day in November. Calculate your reorder point using the expected velocity for the upcoming period, not the trailing average. EZstock lets you override the auto-calculated velocity with a seasonal estimate before generating the reorder suggestion.

Step-by-Step: Set Up Low Stock Alerts with EZstock

EZstock automates the reorder point calculation and puts it into a live dashboard. Here is the full setup process:

1. Install EZstock from the Shopify App Store

   The 14-day free trial activates immediately — no credit card required. EZstock is an embedded Shopify app, so it lives inside your Shopify Admin. After installation you will see a new "EZstock" item in your left sidebar.

2. Connect your products

   EZstock reads your Shopify product catalog automatically via the Shopify API. Every variant that has inventory tracking enabled will appear in the low-stock dashboard. No CSV import or manual mapping needed.

3. Add your suppliers and set lead times

   Go to Suppliers → Add Supplier. Enter the supplier name, their lead time in business days, and their default email address. Lead time is the key variable in the reorder point formula — EZstock cannot calculate accurate reorder points without it. Add one supplier record per vendor you use.

4. Review and set reorder points

   On the Products page, EZstock shows a suggested reorder point for each variant, calculated from your last 30 days of Shopify order data and the lead time of the assigned supplier. Review the suggestion and adjust the safety stock multiplier or enter a custom number if you know your product has unusual demand patterns. Save the reorder point for each product.

5. Configure email alerts (optional)

   By default, EZstock flags products on the low-stock dashboard as soon as quantity falls to or below the reorder point. You can also enable email alerts under Settings → Notifications. Set the alert recipients — typically your purchasing manager or yourself — and choose whether to receive a daily digest or an immediate alert per product.

6. Convert any alert to a purchase order in one click

   From the low-stock dashboard, click any flagged product and select "Create PO." EZstock pre-fills the supplier, the suggested order quantity (based on your reorder quantity setting), unit cost, and delivery address. Review the draft, adjust quantities if needed, and click Send — the PO is emailed to your supplier as a PDF. When stock arrives, mark the PO as received and EZstock updates your Shopify inventory automatically.

Reading the Low-Stock Dashboard — What Each Number Means

Once your reorder points are set, the EZstock low-stock dashboard becomes your primary inventory command center. Here is what each column means:

• Current Stock: live inventory pulled from Shopify. Updates every time an order is placed or a PO is received.
• Reorder Point: the threshold you set (or EZstock calculated). Products at or below this number are flagged.
• Days of Stock Remaining: current stock ÷ daily sales velocity. The most actionable number — it tells you how many days until you stock out at the current sales rate.
• On Order: units in any open (not yet received) purchase orders. EZstock accounts for on-order stock so you are not creating duplicate POs.
• Suggested Reorder Qty: quantity EZstock recommends for your next PO, based on your target stock level and current inventory position.
• Status: OK (above reorder point), Reorder (at or below), or Critical (below safety stock — order immediately).

From Alert to Purchase Order in One Click

The reason most low-stock alert systems fail is the gap between alert and action. You get an email saying "Widget A is low" and then you have to: find the supplier's contact details, look up your last PO to remember what you paid, draft a new email, attach a list of what you need, and wait for a reply. That gap introduces delays — and delays cause stockouts.

EZstock closes the gap. Every alert on the low-stock dashboard has a "Create PO" button. Clicking it opens a pre-filled purchase order with:

• The supplier automatically selected (based on the product's supplier assignment)
• The suggested order quantity pre-populated
• The last known cost price filled in
• Your store's delivery address
• A clean PDF that your supplier can action immediately

From dashboard alert to sent purchase order takes under 60 seconds for a standard replenishment. If you are reordering from multiple suppliers, you can select several products and batch them into a single PO per supplier — EZstock groups them automatically.

What happens when stock arrives

When your supplier ships, they typically send a tracking number or invoice. In EZstock, open the purchase order and click "Mark as Received" (or enter partial quantities if the delivery is split). EZstock immediately updates the relevant Shopify inventory quantities — no manual adjustment in Shopify Admin needed. The dashboard refreshes and the product moves from "Reorder" status back to "OK."