2 November 202311 minute read

How To Calculate Reorder Points & Use the ROP Formula


With Circuit for Teams, optimizing your delivery routes becomes hassle-free, allowing you to focus on fine-tuning aspects like your reorder point formula for better inventory management.

If you’ve ever experienced the inconvenience of stockouts or the financial drain of overstocking, you know just how essential good inventory management is to your business. 

One cornerstone of effective inventory management is understanding your reorder point — the precise moment when it’s time to bring in new inventory. The reorder point formula is a strategic tool that can save you time, money, and a whole lot of stress.

In the fast-paced world of eCommerce and retail, timing is everything. Getting your reorder points wrong can lead to lost sales, increased carrying costs, and even damage to your brand reputation. 

That’s why it’s not just about knowing how to calculate these points but also understanding the factors that influence them, such as safety stock levels, lead time, and customer demand.

Key takeaways

  • The reorder point (ROP) is a critical metric in inventory management. It tells you exactly when to reorder stock to avoid both stockouts and overstocking, helping you achieve just-in-time (JIT) inventory, reduce carrying costs, and meet customer demand effectively.
  • The basic formula for calculating the reorder point is lead time demand + safety stock. Understanding this formula is central to effective inventory management.
  • Reorder points aren’t a “set it and forget it” metric. Revisiting is needed to adapt to changes in demand, supply chain disruptions, or changes in lead time to maintain an optimal inventory level.
  • Your reorder point shouldn’t exist in a vacuum. It should be aligned with your broader supply chain strategies to improve supplier relationships and overall business efficiency.
  • Automating the calculation process using specialized inventory management software can minimize human error and make the process more efficient as your inventory scales.
  • The more often you compare your forecasted figures with actual performance, the more accurately you can adjust your reorder points moving forward.
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What is reorder point (ROP)?

The reorder point (ROP) is that “uh-oh” moment when you realize your inventory is running low and you need to place a new order, pronto! 

In more formal terms, it’s the specific level of inventory at which you should place a new order to replenish your stock before running out. Think of it as your safety net. 

It prevents you from reaching the point where you have to put up an “out of stock” sign, disappointing customers and losing sales.

Why does this matter? 

Having a defined reorder point takes the guesswork out of your inventory management. It makes sure you’ll have enough stock on hand to meet customer demand while you wait for your new stock to arrive. 

No more frantic last-minute orders or wasted storage space filled with products that aren’t selling fast enough.

Understanding ROP is critical in maintaining delivery time commitments to your customers. 

A good ROP strategy goes hand in hand with an efficient inventory management system, which can give real-time reorder level alerts. 

This real-time tracking helps to optimize your replenishment cycles based on average demand, reducing the likelihood of overstocking or understocking.

So, in a nutshell, the reorder point is the inventory level that triggers a new purchase order. 

It’s your cue to take action and make sure your business keeps humming along smoothly with just the right amount of inventory on the shelves.

Importance of ROP in inventory management 

importance of reorder points

You might think that keeping track of when to reorder stock is a no-brainer you can do off the top of your head. But inventory management is a juggling act, and knowing your reorder point (ROP) is like having an extra set of hands to keep all those balls in the air. 

Here’s why it’s so crucial:

  • Avoiding stockouts. Imagine a customer visiting your online store. They’re ready to make a purchase, only to find that the product they want is out of stock. Not only have you lost a sale, but there’s a good chance that customer may think twice before returning to your store in the future. This scenario can lead to lost sales. Calculating your ROP effectively helps you avoid this disaster by ensuring you reorder products before they run out.
  • No more overstocking. On the flip side, ordering too much stock isn’t a good strategy either. Overstocking means you have capital tied up in products sitting in a warehouse or on your shelves. That’s money you could be using elsewhere in your business. Plus, storage isn’t free — you’re racking up carrying costs like storage fees, insurance, and even the risk of product obsolescence. Having a well-calculated ROP helps you order just enough to meet customer demand without excess.
  • Best clash flow management. When you know your reorder points, you can predict your inventory costs more accurately. This makes budgeting easier and allows for better cash flow management. After all, better financial planning can be the difference between your business thriving or just surviving.
  • Improved customer satisfaction. Customers love consistency. They want to know that when they come to your store — whether online or a physical location — they can find what they’re looking for. A well-managed ROP confirms you’re meeting customer expectations by always having enough stock on hand. This boosts customer loyalty and encourages repeat business, which is often more cost-effective than acquiring new customers.
  • Boosting your bottom line. The ultimate goal of any business is to be profitable, and effective inventory management is key to achieving that. By knowing your ROP, you can avoid the financial pitfalls of stockouts and overstocking, improve customer satisfaction, and manage your cash flow better.

How to calculate your reorder point

Calculating your reorder point is a precise process that involves several components and a bit of number crunching. Don’t worry, though — we’re going to break it down into digestible bits, so you can get this crucial part of your inventory management spot-on.

Key components of the reorder point formula 

Understanding the elements that go into the reorder point formula is half the battle. Let’s dissect each of these components to understand why they’re so important and how they influence your reorder point.

Lead time

Ever ordered something online and then had to wait a bit before it arrived at your door? That waiting period is what we call “lead time.” 

In the context of inventory management, lead time is the amount of time it takes for a new order to be delivered to your warehouse once you’ve placed a purchase order. 

The lead time is a critical element in calculating your reorder point because it helps you predict when your new stock will arrive. If your lead time data is off, you risk either overstocking or ending up with empty shelves. 

It’s crucial to use accurate and updated lead time information for precise reorder point calculations. 

Safety stock

Life is full of surprises, and so is your inventory. 

Safety stock acts as your buffer against those “oops” moments — like sudden spikes in demand or delays in your supply chain. Think of it as your insurance policy against stockouts.

Here’s the safety stock formula:

Safety stock = (maximum daily use x maximum lead time) - (average daily use x average lead time)

This formula accounts for fluctuations in both average daily usage and lead times. By taking the maximum and average scenarios into account, you can better safeguard against stockouts or overstocking.

Having an adequate safety stock level means you’re covered when those unexpected scenarios pop up. It gets factored into your reorder point to make sure you’re always prepared.

Demand rate

To keep those shelves stocked just right, you need to know how quickly your products are selling — that’s your demand rate. 

Understanding customer demand helps you set a reorder point that aligns with actual buying patterns, so you neither overstock nor run out.

Average daily sales

This metric is exactly what it sounds like: the average number of units sold per day. Calculating your average daily sales gives you a realistic snapshot of your demand rate. 

By knowing how much you sell on an average day, you can set more accurate reorder points.

Reorder point formula 

Ready for the formula?

Reorder point = lead time demand + safety stock

reorder point calculation

Reorder point calculation 

Now that you’re familiar with the terms, let’s go through a step-by-step guide to calculate a reorder point using an example.

  1. Determine your average lead time. This is the period needed for your supplier to deliver new inventory after you’ve placed a purchase order.
  2. Calculate your average daily sales. This involves dividing the total sales over a period by the number of days in that period.
  3. Calculate lead time demand. Multiply the average daily sales by the average lead time. This tells you how many units you’ll need to meet customer demand during the lead time.
  4. Determine your safety stock. This is a predetermined number of units that serves as a cushion for unexpected events, like a surge in demand or supply chain disruptions.
  5. Calculate reorder point. Add your lead time demand to your safety stock. The result is the inventory level at which you’ll need to reorder new stock.

While it’s doable to handle these calculations manually, it can be a task as your inventory scales up. You might consider using tools like Excel or specialized inventory management software to keep track of your numbers more efficiently.

Calculating the reorder point for an eCommerce business 

Now that you’re acquainted with the general steps and the formula, let’s go through a detailed example. We’ll take the hypothetical case of an eCommerce business that sells smart home gadgets.

Initial data:

  • Lead time: 10 days
  • Average daily sales: 50 units
  • Safety stock: 100 units

Step-by-step calculation

  1. Determine your average lead time. In our example, the average lead time is 10 days. This means it takes 10 days from the moment you place a new order until that inventory arrives in your warehouse.
  2. Calculate your average daily sales. Our eCommerce business has an average daily sales rate of 50 units. This number is typically calculated by taking the total number of sales over a certain period and dividing it by the number of days in that period.
  3. Calculate lead time demand. Here, you’d multiply the average daily sales by the lead time:
  4. Determine your safety stock. Use the following safety stock calculation: 
  5. Calculate your reorder point. Finally, you add the lead time demand to your safety stock to get your reorder point:

With a reorder point of 720 units, you’d place a new order when your inventory level drops to this number. 

By doing so, you confirm you have enough stock to cover the sales during the lead time, plus an additional safety stock to cover unexpected demand or supply delays.

Best practices for setting reorder points

reorder point best practices

Setting up a reorder point is not a task you only have to do once. Ensuring that your inventory is well-maintained involves regular adjustments and strategic planning. Here are some best practices to help you manage your reorder points effectively.

Keep updating your numbers 

In an ideal world, your reorder points would be static. However, we don’t live in an ideal world. Things change often, unpredictably, and quickly. 

Market trends evolve, suppliers update their terms, and seasonal changes can impact your sales.

Revisiting your reorder point calculations on a regular basis — whether monthly, quarterly, or even weekly depending on your business type — will make sure you don’t get caught off guard by market shifts or changes in your supply chain.

Find the sweet spot 

The pitfalls of maintaining too much or too little inventory are both risky, albeit for different reasons. 

Overstocking not only takes up valuable warehouse space but also increases your carrying costs, which include utilities, security, and insurance for the items stored. 

On the flip side, understocking risks customer dissatisfaction, missed sales opportunities, and tarnishing your brand reputation.

Setting an optimal reorder point is an act of balance. This means a close understanding of your carrying costs, storage capacity, and, most importantly, your customer buying habits. 

Regular reviews can help you maintain this crucial balance.

Try advanced predictions 

The use of advanced forecasting techniques is like having a weather report for your sales climate. Methods such as time-series analysis, causal models, and machine learning algorithms can give more nuanced insights into customer demand patterns and seasonal fluctuations.

Data analytics can reveal surprising trends, like which products are likely to be hot sellers during specific times of the year or even which items frequently get bought together. 

This information is invaluable for setting reorder points that are not only effective but also efficient.

Use software tools 

Manually managing reorder points is possible but hardly efficient, especially as your business grows. 

Modern inventory management software can automate this process, reducing the likelihood of human error and freeing up your time for other critical business tasks.

These software solutions often come with features that alert you when stock reaches the reorder point or even automatically place orders with suppliers, ensuring a seamless inventory management process.

Work closely with your supply chain partners 

Reorder points are a key element in a larger supply chain ecosystem that includes suppliers, manufacturers, and logistics providers. 

Collaborative relationships among these entities are critical for setting reorder points and also for overall business efficiency.

Regular meetings, performance reviews, and strategic discussions can help you and your partners adapt to market trends, anticipate challenges, and make the most out of opportunities, resulting in more accurate reorder points.

Pay attention to SKUs 

Each product in your inventory likely has its own stock-keeping unit (SKU), a unique identifier that makes it easier to track for inventory purposes. 

It’s a mistake to assume that a single reorder point strategy will work for all products.

Each SKU may have its own demand curve, lead time, and safety stock requirements. So, each needs its own reorder point for effective inventory management. 

This becomes even more critical if you’re dealing in products with varying seasonal demands, shelf-lives, or supplier terms.

Frequently asked questions (FAQ) about ROP

Inventory management can be a complex field with a lot of acronyms and terms that might be confusing at first. Here, we’ve gathered some of the most commonly asked questions about reorder points (ROP) to help demystify the process.

What is the reorder formula? 

The basic Reorder Point formula is:

Reorder Point = lead time demand + safety stock

In this formula, lead time demand is calculated by multiplying the average number of units sold per day by the average lead time in days. 

Safety stock serves as a buffer for unpredictability in demand or supply. 

By adding these two components together, you determine the inventory level at which you’ll need to place a new order to replenish stock before running out.

What are ROP and EOQ? 

Reorder point (ROP) and economic order quantity (EOQ) are two essential metrics in inventory management, but they serve different purposes.

  • Reorder point (ROP). This is the inventory level at which you should place a new order to replenish stock before it runs out. It takes into account lead time and safety stock to prevent stockouts.
  • Economic order quantity (EOQ). This is the ideal number of units to order to minimize the total inventory holding costs and ordering costs. It’s a more complex calculation that considers things like carrying costs, demand rate, and the cost to place an order.

Both ROP and EOQ are crucial for effective inventory management but are used at different stages and for different aspects of the inventory management process.

How often should I update my ROP? 

Review and update your reorder points regularly. The frequency of these updates can depend on various factors like market volatility, seasonality, and changes in consumer demand. 

For fast-moving consumer goods, you might need to review the ROP weekly, whereas for other types of inventory, a monthly or quarterly review might be good enough.

How does ROP affect delivery time? 

Understanding your ROP can actually help you get your products out to customers faster. 

Why? Because knowing your ROP tells you exactly when you need to order more stuff before you run out. 

When you order at the right time, you make sure you’ve always got something to sell, and you don’t have to wait for a new shipment to come in to keep delivering to your customers.

So, if you get your ROP right, you’re not going to run out of products. Running out means you have to tell your customers to wait longer, which no one likes. 

It’s frustrating for them and not good for your business.

Also, when you’re not stressed about running out of items, you can focus on other things like figuring out the best way to get your products shipped. 

Maybe you can even get a deal on faster or cheaper shipping because you’re not in a rush.

Close the inventory management loop with Circuit for Teams

Calculating reorder points is a critical part of inventory management, but it’s not the only piece of the puzzle. 

Once you’ve mastered the art of when to reorder, the next challenge is getting those products into your warehouse and then into the hands of your customers as efficiently as possible. 

That’s where Circuit for Teams comes in.

Specializing in last-mile delivery logistics, Circuit for Teams makes sure your well-calculated inventory arrives exactly where it needs to be and when it needs to be there. 

With features like real-time tracking, optimized routing, and proof of delivery, you can eliminate uncertainties and enhance customer satisfaction.

Ready to experience the Circuit for Teams advantage? Sign up today.

About the author

Heather Reinblatt
Heather ReinblattContributor

Heather Reinblatt is a managing editor currently living in St. Louis, Missouri. She spends her free time reading, trying new recipes, and cuddling her cat Paisley. You can find Heather on LinkedIn.


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