A stockout is an inventory event that happens when a business runs out of a product customers want to buy, resulting in lost sales. Keep the right goods on hand and you protect revenue, customer trust, and your reputation. Run short, when demand outpaces supply or you fail to hold enough inventory, and you hand those sales to a competitor.
The stakes reach well beyond a single empty shelf. According to IHL Group, global retailers lose $1.73 trillion a year to inventory distortion, the combined cost of out-of-stocks and overstocks. This guide explains what causes stockouts, what they cost, and how to prevent them.
Key takeaways
- A stockout happens at the point of sale when depleted inventory leaves a product customers want unavailable, which directly costs sales.
- Common stockout causes include inaccurate records, forecasting errors, supplier delays, cash flow gaps, and order-processing limits.
- Recurring stockouts damage brand reputation, raise backorder and lead-time costs, and push loyal customers toward competitors.
- Preventing stockouts relies on real-time inventory data, accurate forecasting, safety stock, and disciplined reorder points.
What is a stockout?
A stockout occurs when a business runs out of a particular product, so customers can’t buy the item and you lose the sale. Being out of stock occasionally is normal for any business. But monitoring items and communicating low inventory early keeps commerce smooth for everyone involved.
“Stockout” and “shortage” are often used interchangeably, but they aren’t quite the same. A shortage usually points to a broader supply chain issue that prevents replenishment. For example, you might face shortages due to supplier delays, logistics disruptions, or insufficient raw materials.
Stockouts, on the other hand, happen at the point of sale, where the item customers want is unavailable because of depleted inventory. You may have forgotten to reorder on time or underestimated demand. Or a shortage caused it: you ordered what you needed, but your supplier couldn’t fill the order.
To determine whether you have a stockout problem, calculate your stockout rate:
Stockout rate = Number of out-of-stock products / Number of in-stock products
This measures how often stockouts occur. A lower percentage means they’re rare, while a higher percentage means worse inventory performance.
Navigating stockouts well takes close attention, starting with your website. When you’re out of a product, update its availability status so you don’t accept orders for goods you don’t have. To keep product flowing, put the right systems in place beforehand to spot low stock early.
What are the 8 common causes of stockouts?
Watching your logistics, suppliers, and cash flow keeps stockouts from disrupting the business. Here’s how they happen.
1. Inaccurate records
Human error is the most frequent culprit behind stockouts. Inventory miscounts or clerical errors when updating spreadsheets make you think you have more items than you actually do. By the time you discover the error, it’s usually too late.
Shy away from manual inventory counting processes. Instead, adopt inventory management software that maintains real-time stock data and flags issues early, such as Fishbowl. Fishbowl Inventory connects directly to QuickBooks to keep your stock levels and your costs in check.
2. Delivery and logistics problems
You can do everything right (track inventory levels, reorder on schedule, and stay in contact with your supplier) and a stockout can still happen. Logistical or delivery problems are often out of your control.
Severe weather or a mechanical breakdown can cause delivery delays. That leaves you without the items you need to keep shelves stocked and ready for purchases.
3. Miscalculated forecasting
Inventory forecasting helps you align your strategy with consumer demand, and a miscalculation can lead to stockouts or overstocks. Overstocks increase your holding costs, create inflexibility in your warehouse, and diminish liquidity. Stockouts cause shortages that make customer demand hard to meet, so solid forecasting balances the two.
4. Poor cash flow management
Poor cash flow management can leave you without the resources to reorder items on time. Cash flow issues arise when you over-order or hold the wrong inventory, so you then offload it through sales or deals.
5. Supplier delays
Suppliers are sometimes late delivering materials or completing orders, which can lead to stockouts. That’s why it helps to have a diverse supplier network and to pivot quickly if your go-to supplier doesn’t meet your needs.
6. Manufacturing issues
Problems on the production floor become inventory problems. If equipment failures or labor shortages interrupt manufacturing timelines, your stock may run out before replenishments are ready. If a batch has quality issues, you may have to discard the affected units, creating unexpected gaps in availability.
7. Unexpected increases in demand
Sudden surges in demand can empty your shelves faster than your supply chain can respond. These stockouts are hard to predict. They may be driven by unpredictable factors like viral trends or seasonal spikes that exceed your typical sales patterns.
8. Processing capacity
If the system you use to process orders is outdated or poorly integrated with your inventory tools, you may sell more items than intended. Overselling quickly depletes your inventory, resulting in stockouts that disrupt sales. This is especially damaging if you can’t cover the sales you’ve already made.
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What do stockouts cost your business?
While your business can survive the occasional stockout, recurring shortages eventually take a toll on your reputation, bank account, and customer satisfaction. For a small or up-and-coming business, stockouts can even be devastating.
The losses add up fast across the industry. In 2022, IHL Group found North American retailers faced up to $349 billion in inventory distortion losses (out-of-stocks and overstocks combined), according to Supermarket News.
Better inventory control reverses that trend. Hodo Foods, a plant-based food producer, cut stockouts by 35% after moving to Fishbowl. Here’s what’s at stake when you don’t act.
1. Bad reputation
You don’t want to become a brand that never has adequate inventory. Customers might forgive the occasional shortage, but some will leave negative reviews when they can’t get the products they want. That tarnishes your brand and creates a vicious cycle that costs you future business.
While that may sound alarmist, your reputation is incredibly valuable. Protecting it means protecting your inventory, too.
2. Loss of sales
Unless an item is a limited edition or brand exclusive, customers can probably find a comparable alternative somewhere else. Think about the last time you visited a convenience store that didn’t have your favorite snack. Did you go home and wait for a restock, or leave and visit another store?
Your customers share that mentality, especially when the item is something they want or need immediately. Stockouts lead customers right to competitors.
3. Backorder costs
You can always accept backorders to offset the inconvenience of stockouts, but customers won’t wait forever. To avoid cancellations, you’ll need to expedite shipments and communicate constantly. That keeps customers happy, but it drives up shipping costs and cuts profit margins.
4. Longer lead times
Lead times have a direct impact on customer satisfaction. Short lead times make for happier customers, while longer ones tend to frustrate people, especially when they wait longer than expected.
Stockouts drive up your lead times and create the perception that your brand is unresponsive or slow to fulfill orders.
5. Decreased customer loyalty
Product availability has a major impact on customer satisfaction. If customers find a similar product when yours isn’t available, they may buy from a competitor or switch brands altogether. What started as a minor inconvenience just cost you a loyal customer.
How do you prevent and manage stockouts?
Sometimes stockouts are outside your control. But that doesn’t mean you shouldn’t aim to prevent them, or at least minimize their impact. Here are a few strategies for doing so.
1. Improve inventory management
Start by evaluating the accuracy of your inventory management practices. If you rely on manual counts, adopt modern software that reduces human error and gives real-time insight into availability. Most solutions also include automation tools to save you time.
2. Optimize forecasting
Accurately anticipating customer demand helps you hold the right amount of inventory. No forecast is perfect, but modern forecasting tools guide your strategy and significantly reduce stockout probability. You can also adjust inventory levels more easily as consumer demand shifts.
3. Keep an eye on your supply chain
Monitor your supply chain closely and maintain open lines of communication with your suppliers and vendors. The sooner you know about a potential supply issue, the more time you have to pivot. And if a particular vendor frequently lets you down and delays shipments, it’s time to find a new trading partner.
Don’t wait until a problem arises to seek out new supplier relationships. Put those partnerships in place now so you have clear alternatives when a supplier has missed deliveries one too many times.
4. Maintain safety stock
Safety stock is a surplus of a product that protects against stockouts. Imagine you order 1,000 units of a stock keeping unit (SKU) each month and sell about the same. An unexpected shipping delay could lead to a shortage, but safety stock buys you time.
Sizing that buffer well matters, so use a proven safety stock formula to set the right level for each product. Safety stock is for emergencies; recalculate your reorder points if you’re routinely cutting into it. Those points reveal when to order more.
5. Monitor average replenishment times
Watch your average replenishment time. It measures how long it takes to get products on the shelf after you place an order. Also monitor your inventory turnover ratio, which tracks how often you sell through stock in a period.
When you know how long replenishment takes and how quickly you sell through stock, you can optimize reordering to minimize risk. Even if a stockout happens, you’ll know roughly when products return and can share that with customers to reduce frustration.
6. Implement PAR level controls
Periodic automatic replacement (PAR) levels are the minimum number of inventory units needed to operate smoothly. Set PAR controls for each product, and when inventory dips below the minimum, reorder automatically to prevent stockouts.
7. Conduct routine inventory audits
Regular inventory audits help you catch the errors that contribute to stockouts. By doing physical counts and comparing them to your records, you can spot discrepancies early and correct them before they disrupt operations.
Maintain healthy stock levels with Fishbowl
Preventing stockouts starts with modernizing how you track inventory, and that starts with Fishbowl.
Fishbowl gives you real-time control over stock levels across every location, so you can reorder on time and stop guessing. Fishbowl Inventory delivers up-to-the-minute visibility into what you have and what you need. Fishbowl Warehousing adds automated purchasing, vendor management, and order approvals in one platform.
Together, Fishbowl’s inventory and warehousing tools unify your data and speed up decisions with clear reporting.
Frequently asked questions about stockouts
How much safety stock should you keep to avoid stockouts without tying up cash?
Size safety stock to your demand variability and lead-time variability, not a flat percentage across every product. Set higher buffers for fast-moving or hard-to-replace items and leaner ones for stable, low-risk products. Recalculate reorder points on a regular schedule so you cover real risk without parking cash in inventory you rarely touch.
How do you reduce inventory carrying costs without risking stockouts?
Focus your capital where it protects the most revenue. ABC analysis ranks products by sales value, so you can hold tighter buffers on top sellers and trim overstock on slow movers. Pair that with accurate forecasting and disciplined reorder points, then use Fishbowl AI Insights to build those reports in plain language.
How do you know if your current inventory process is costing you sales?
Watch for a rising stockout rate, frequent backorders, and repeat complaints about items you can’t fulfill. Manual counts, spreadsheet updates, and a lack of real-time visibility usually signal a process that leaks sales. If you’re discovering shortages only after customers do, your inventory system isn’t keeping pace with demand.
How can you avoid stockouts during peak season?
Start with your own sales history from prior peak seasons. Forecast demand from those peaks, then raise safety stock ahead of the surge instead of reacting once shelves empty. Diversify suppliers so one delay can’t stall replenishment, and watch stock in real time to reorder the moment levels dip.
Can AI actually reduce stockouts?
Yes, within limits, because AI sharpens the inputs rather than running inventory on its own. It improves demand forecasting and surfaces replenishment signals earlier, which helps you act before stock runs out. Fishbowl AI Insights lets you query inventory data in plain language and build custom reports without SQL, so at-risk items surface faster.
Related posts
Explore more Fishbowl guides on preventing stockouts and managing inventory:
- Stock replenishment: Methods and best practices
- Calculating the Safety Stock Formula: 6 Methods + Key Use Cases
- How to Avoid Product Stockouts
- Reorder Point Formula: How to Calculate Safety Stock
- Increasing Customer Satisfaction by Avoiding Stockouts
- How does ABC analysis improve inventory management?
- How to calculate lead times to improve your bottom line