Flieber Blog

For Amazon sellers, Prime Day is one of the most anticipated events on the calendar. It consistently ranks among the highest-volume sales days of the year, and for many brands it represents a significant share of annual revenue. But Prime Day is also one of the most unforgiving events from aninventory planning perspective.

For most ecommerce brands, inventory management looks something like this: a spreadsheet, a dashboard, a weekly report someone pulls manually, and a standing meeting to review numbers that are already a few days old by the time the team sees them.

Inventory is one of the most important — and most misunderstood — drivers of profitability in ecommerce. Most brands think about inventory primarily from an operational standpoint. Do we have enough stock? Are shipments arriving on time? Can we fulfill customer orders quickly enough?

For years, spreadsheets were the default solution for inventory planning in ecommerce. They were flexible, inexpensive, and familiar. In the early stages of an Amazon business, a spreadsheet could handle forecasting, reorder calculations, supplier tracking, and inventory monitoring well enough to support growth.

Inventory forecasting used to be relatively straightforward.

Brands looked at historical sales trends, estimated future demand, and reordered inventory accordingly. But ecommerce has changed dramatically over the last several years. Customer behavior moves faster, trends emerge overnight, and a single viral moment can completely disrupt months of inventory planning.

Demand planning has always been important in ecommerce, but in recent years, it has become significantly harder to get right.

Consumer demand moves faster than ever. A product can suddenly spike because of a TikTok video, a creator mention, or a successful ad campaign. Seasonal trends shift unexpectedly. Marketplace algorithms change overnight. At the same time, ecommerce brands are managing inventory across more channels, more SKUs, and more fulfillment locations than ever before.

Inventory planning and inventory management are often grouped together, and while they are closely connected, they serve very different purposes within an ecommerce business. Understanding that difference is critical for brands trying to grow efficiently, protect margins, and avoid the constant cycle of stockouts and excess inventory.

Most ecommerce brands believe they have supply chain visibility.

What Are Demand Planning Models? (Quick Answer)

Demand planning models are frameworks used to predict future customer demand based on historical data, trends, and external variables. These models help ecommerce brands make better decisions around inventory, purchasing, and supply chain operations.

If you’re running an ecommerce brand in the $5M–$100M range—especially across Shopify, Amazon, and wholesale—demand planning stops being optional.