What Is a Reorder Point and How Do You Set One?

You've calculated your safety stock. You know you should keep 310 units on hand as a buffer. Now the question becomes: when do you actually place the order?

That's what a reorder point answers. It's the inventory level at which you need to place a new purchase order, based on how much you'll sell while waiting for the next shipment to arrive. Get it right, and you reorder before you run out. Get it wrong, and you either stockout waiting for delivery or accumulate excess inventory.

A reorder point is straightforward to calculate once you understand the concept. But many businesses skip it entirely, relying instead on gut feeling or panic ordering. That approach holds up until it doesn't, and when it fails, the cost hits fast.

What Is a Reorder Point?

A reorder point (ROP), also called a reorder level, is the minimum inventory level at which you should place a new purchase order with your supplier. It's the trigger that says, "Order now, before you run out."

The reorder point tells you when to reorder. That's a separate question from how much to order, which is the economic order quantity we'll touch on shortly. Different concepts, different calculations, same goal: keeping the right amount of stock on hand at the right time.

Without a reorder point, you're managing by crisis. You wait until you're nearly out of stock, panic, and place an emergency order that costs more and arrives later. With one, you place a calm, planned order when you reach a predetermined level, giving your supplier normal lead time to deliver.

In the previous piece, we calculated safety stock as the buffer that protects you when things go wrong. The reorder point is where you act before things go wrong.

The Reorder Point Formula

The formula is simple:

Reorder Point = (Average daily sales x Lead time in days) + Safety stock

You already have most of this from the safety stock calculation. Let's break it down:

Average daily sales: How many units you typically sell per day (total sales over a period divided by number of days)
Lead time in days: How long it takes your supplier to deliver an order
Safety stock: The buffer you calculated in the previous piece

Working Through a Real Example of Setting a Reorder Point

Let's use the same product from the safety stock example to show how these pieces connect.

You determined that:

Average daily sales: 50 units
Lead time: 5 days
Safety stock: 310 units

Now calculate your reorder point:

Lead time demand = 50 units/day x 5 days = 250 units
Reorder point = 250 + 310 = 560 units

This means: when your inventory drops to 560 units, place a new order.

Here's what happens next:

You place an order at 560 units
Over the next 5 days, you sell your normal 250 units
Your inventory drops to 310 units (your safety stock)
The new shipment arrives, bringing you back up to your target level

If everything goes normally, that 310-unit safety stock buffer sits unused. But if demand spikes to 80 units per day during those 5 days, or if the supplier takes 7 days instead of 5, that buffer protects you from a stockout.

Reorder Point vs. Economic Order Quantity: Two Different Questions

These terms often get confused, so it's worth clarifying.

A reorder point answers: When do I place an order? Economic order quantity (EOQ) answers: how much should I order? An independent finance educator's breakdown of EOQ and ROP frames it well, with the reorder point setting the timing of the order and the EOQ setting its size.

Using the example above:

Your reorder point is 560 units (the trigger level)
Your EOQ might be 2,000 units (the quantity that minimizes total ordering and holding costs)

So when inventory hits 560, you don't order just 250 units to get back to your target level. Instead, you order 2,000 units, because that's the quantity that balances the cost of placing frequent small orders against the cost of holding excess inventory.

After the 2,000-unit order arrives, your inventory jumps to 2,560 units. As you sell, it drops back toward the 560 reorder point. When it hits 560 again, you order another 2,000.

This two-step approach, knowing both when and how much, is the backbone of efficient inventory management.

When Your Reorder Point Needs Adjustment

Like safety stock, your reorder point shifts as your business changes. Recalculate it when:

Demand patterns change. A seasonal shift, a successful promotion, or a new sales channel means your average daily sales are no longer accurate. Recalculate to reflect the new baseline.

Lead times shift. A supplier delays consistently, or you switch to a faster shipper. Either way, lead time changes affect when you need to order.

You add or lose a major customer. A big customer starts ordering regularly, or a contract ends. Recalculate based on the new demand pattern.

Your business is growing rapidly. Year-old data becomes unreliable when this year's sales are significantly higher. Adjust your reorder point upward so historical patterns don't cap your ability to serve demand.

The best practice: review reorder points quarterly. If your business is seasonal or growing quickly, review monthly. Update immediately if anything in your supply or demand changes significantly.

The Math Looks Simple. The Execution Isn't.

The formula itself is straightforward. But accurately calculating and maintaining reorder points across dozens or hundreds of products requires:

Accurate sales history (which requires real-time visibility into what actually sold across all channels)
Reliable lead time data (which requires tracking what you ordered, when, and when it arrived, especially when you're managing inventory problems across a growing operation)
A system that flags when inventory approaches the reorder point

Most small businesses start with spreadsheets. For a few products, that works. But as your catalog grows, manually tracking reorder points becomes tedious and error-prone. You'll miss a recalculation, forget a product, or miscalculate an average. One missed reorder can trigger a stockout that costs more in emergency shipping and lost sales than the whole spreadsheet ever saved.

This is where inventory management systems, whether standalone or built into an ERP platform, start to earn their keep. When your sales data and purchase order history live in one system, calculating and monitoring reorder points becomes automatic. The system flags when you're approaching the reorder point, can even generate a purchase order suggestion, and tracks whether the formula is actually working. If you're weighing that step, start with the best ERP options for eCommerce.

Set It, Monitor It, Adjust It

A reorder point is only useful if you act on it. That means one of three approaches:

Manual review: Someone checks inventory daily and places an order when it hits the reorder point
Automated alerts: A system flags when you're at or near the reorder point, and you place an order
Full automation: The system generates a purchase order automatically when inventory hits the reorder point

Manual works for a handful of products. Alerts work for a small team with moderate inventory. Full automation becomes the practical choice once you're managing enough SKUs that manual tracking turns unreliable.

As your business scales, maintaining accurate reorder points across all your products gets more complex. Learn how to prevent stockouts and backorders as you grow.

Connect the Dots: Safety Stock, Reorder Point, and Stockout Prevention

Safety stock tells you how much buffer to carry. Your reorder point tells you when to order. Together, they create a system that prevents stockouts without tying up excessive capital.

The reorder point is the moment of action. It's where inventory management theory meets the real work of running your business. Get it right, and your supply chain runs smoothly. Get it wrong, or skip it entirely, and you'll spend your time firefighting when you could be planning.

Ready to see how reorder points work in a connected inventory system that tracks and calculates them automatically? Click below to start your Free ERP Deployment.