Many e-commerce companies make unnoticeable profits and losses due to poor inventory management. High sales on the surface may lead to cash flow issues, late orders, overselling, and wasted storage costs. For online retailers, it’s not simply a matter of having “enough inventory.” The actual challenge is to have the right stock in the right place at the right time, with the right data behind every decision.
Inventory management is the management of products from purchase to delivery. For e-commerce, it relates to inventory, reorder points, warehouse storage, inventory accuracy, product availability, returns, and fulfillment speed.
A seller with poor inventory management tends to respond too late. They reorder when products have already run out, identify slow-moving products when storage costs rise, or detect an inventory error when a customer places an order. A seller with effective inventory management has a head start, as the data is available before a problem becomes costly.
Why Inventory Management Matters in eCommerce
Inventory is more than product – That is why inventory management matters! It is money that sits on a shelf! The wrong products languish for too long, and money is tied up in advertising, product development, supplier payments, and new product launches. When the right products are unavailable, sales drop even when demand is there.
The first significant threat is the lack of supplies. In the absence of the product, sellers do not earn immediate income and could be losing the entire customer. Stockouts also undermine marketplace performance by incentivizing sellers who ensure they have a steady supply and delivery.
Overstocking is the second risk. It may seem easier to overstock than to run out, but there are issues with that approach. Excessive inventory leads to higher storage costs, reduced funds availability, and can result in product discounts due to obsolescence, seasonal factors, and slow-moving items.
The third risk is the quality of the fulfillment. An inaccurate inventory can make it difficult to quickly assess the items available in a warehouse. The system may indicate that stock is available, but the product may be damaged, lost, reserved, or not received correctly.
A recent Elsevier stock-out prediction study reported that the number of stocks on hand, the short-term forecast, and the number of sales over the last few years are significant factors in determining the risk of a stock out. That is an obvious fact of operation: it is hard to manage inventory if the data is out of date or incomplete.
What Good Inventory Management Actually Controls
Managing inventory isn’t a single step. It’s a network of smaller controls that are interconnected.
The inventory tracking indicates the status of each item (available, reserved, inbound, damaged, returned, or unavailable). This ensures that sellers cannot presume that all physical stock is available for sale.
Demand forecasting is a method of predicting future demand based on past sales, seasonal trends, marketing initiatives, and product trends. Predictions can’t eliminate uncertainty, but they can minimize blind ordering.
Reorder point planning is a method of determining when to create a new reorder point. Average sales, supplier lead time, freight time, customs clearance, warehouse receiving, and safety stock must all be considered when determining a useful reorder point.
Safety stocks safeguard sellers against demand upsurges, supplier delays, freight disruption, or receiving delays. This is particularly crucial for top-selling items and imports.
Inventory valuation helps sellers determine the amount of money invested in inventory. This is crucial for accounting, cash flow forecasting, and profitability analysis.
Inventory Management Methods Compared
Different inventory methods solve different problems. Sellers do not always need to use every method, but they should understand which one fits their product type and business model.
| Method | What It Means | Best Use Case | Main Watch-Out |
| FIFO | The first stock received is sold first | Beauty, supplements, food, expiry-date products | Requires accurate receiving-date tracking |
| LIFO | The newest stock is sold first | Limited eCommerce use | Older stock may sit too long |
| Weighted Average Cost | Inventory value is averaged across purchase prices | Products with changing supplier costs | Can hide margin changes by batch |
| Just-in-Time | Stock is kept lean and reordered close to demand | Stable suppliers and predictable demand | Risky during freight delays or demand spikes |
| ABC Analysis | SKUs are grouped by value and importance | Catalogs with many products | Needs regular review as sales patterns change |
ABC analysis can be particularly useful for most e-commerce sellers. A-items will generally be the most significant products because they tend to be more profitable, generate higher revenue, or drive higher repeat purchases. These must be monitored more closely, have improved safety stocks, and be replenished more quickly. Moderate control for B-items is required. C-items should not be a significant storage or financial burden.
Many sellers treat all SKUs the same. A slow-moving best seller does not have to be reordered.
Common Inventory Management Mistakes
A common error is over-reliance on spreadsheets. Spreadsheets can be effective for a seller with a small product line and small order volumes. However, manual updates are dangerous once products are sold through Shopify, Amazon, TikTok Shop, Walmart, or other channels. If one of the sheets is not updated on time, it can result in over-selling or under-stocking of replenishment.
The other error is neglecting the overall lead time. Sellers might be aware of the supplier’s production time but forget about freight, customs, warehouse receiving, quality, and put-away. If it takes a supplier 15 days to make goods, but the total time to available stock is 45 days, the reorder plan should be based on 45 days, NOT 15 days.
A third error is failing to remove sellable and unsellable stock. Stock that has been returned, damaged, but not inspected, or stock that has not been inspected and is reserved, should not be included in available stock.
Aliases also cost sellers when they lack an accurate record of returns. Returned items should not be restocked for sale until after they have been inspected. Otherwise, your customers may get damaged or incomplete products.
Last but not least, many sellers focus solely on the value of the inventory as a whole rather than on each SKU’s performance. A business can look healthy, with its most popular products almost sold out and slow-moving products piling up in its warehouses.
Inventory Metrics Sellers Should Track
There are simple yet powerful inventory metrics that are the most useful.
The Inventory Turnover Ratio is a measure of the rate at which inventory is sold and replenished. If turnover is slow, it can be a sign of poor demand, overstocked inventory, or a poor product selection.
The stockout rate indicates the frequency with which a product is unavailable. The seller should have more reorder points or safety stock for important SKUs when they regularly have low stock levels.
The sell-through rate is a ratio of units sold to units received. It comes in handy for seasonal planning and product launches.
Days’ inventory outstanding measures the time it takes to sell the inventory. The longer the stock is held, the more it strains storage costs and cash flow.
Inventory accuracy is the verification of the actual inventory vs. the inventory in the system. This is an important measure because it can lead to overselling, delays, cancellations, and customer service issues.
It’s also important to monitor the return rate per SKU. Refunds, restocking fees, and replacement shipping can make a product look successful until they are added in.
How NextSmartShip Helps with Inventory Management
By integrating inventory visibility and fulfillment operations, NextSmartShip simplifies inventory management. This is crucial for e-commerce retailers as inventory information should not be siloed from order processing. The seller should be aware of which items are available, their locations, and their movement during fulfillment.
NextSmartShip’s inventory management service allows sellers to track their stock and SKUs through a unified system. It helps to make better decisions on replenishment, product availability, and multi-channel order fulfillment.
It also integrates inventory storage with picking, packing, and shipping via its e-commerce fulfillment service. This is important because inventory accuracy isn’t effective if the warehouse process isn’t accurate either.
According to NextSmartShip support documentation, inventories are scanned at the dock upon arrival, and each SKU is placed in a designated location in the warehouse (shelf, bin, pallet, etc.). This SKU-level storage is crucial, as it enables effective inventory management by providing precise information on product locations and how to retrieve them.
NextSmartShip can also be helpful for sellers with a hybrid fulfillment model, helping differentiate fast-moving and slow-moving items. Higher-priced inventory can be kept near customers, and slower-moving items can be kept near lower-cost facilities. This enables retailers to limit stockouts and avoid overallocating funds to local warehousing.
Best Practices for Better Inventory Management
Sellers should forecast demand before placing purchase orders. Past sales, seasons, campaign schedules, and supplier reliability should all shape orders.
You must set a different reorder point for each SKU. We cannot have a single rule for all our products as they have different lead times and sell at different rates.
SKUs that are moving quickly need to be kept under more scrutiny than slow movers. Such products might require safety stock, priority replenishment, and storage in warehouses near customers.
Regular inventory audits are a good practice for sellers. Cycle counts can identify discrepancies before they become major fulfillment issues.
They should also regularly check on products that move slowly. Sellers should price down, package or bundle, broker down future orders, and/or discontinue the weak-turner if a SKU shows weak turnover.
Most importantly, decisions about inventory should be based on total cost. The product’s price isn’t sufficient. When determining whether a SKU is profitable, sellers should consider freight, duties, storage, fulfillment, returns, and discounting.
Conclusion
The key to successful eCommerce fulfillment is inventory management. It minimizes stockouts, avoids overstocking, enhances cash flow, and ensures timely customer deliveries.
The job is not only to increase inventories. The challenge is to maintain the right inventory and manage it properly using trusted information. A seller who knows how to leverage sales velocity, reorder frequency, safety stocks, and warehouse visibility will have a much better chance of scaling.
For better fulfillment, better inventory management for growing eCommerce brands. A great customer experience is achieved by better fulfillment. And the better customer experience leads to long-term growth.