What is the Pareto principle in inventory?

The Pareto principle in inventory is the observation that roughly 20% of SKUs drive approximately 80% of a business's sales, revenue, or inventory value, meaning a small subset of items carries disproportionate financial weight.

In practice, retailers use this 80/20 pattern to decide where to concentrate effort in planning, control, and valuation. The "vital few" high-impact items deserve tighter forecasting, more frequent reorder cycles, and closer stock monitoring. The remaining items, which contribute relatively little to overall value, can be managed with simpler controls or reviewed for consolidation.

The Pareto principle is the conceptual foundation behind ABC analysis, which formalizes the 80/20 split into three categories:

• A-items are the roughly top 20% of SKUs that generate around 80% of revenue or inventory value, and receive the most rigorous tracking and cycle counting.
• B-items are mid-tier contributors that warrant moderate attention.
• C-items are the large volume of low-impact SKUs that contribute a small share of value but can still tie up capital and space.

A few practical notes worth keeping in mind: the 80/20 ratio is an approximation, not a fixed law. Real-world distributions might be 70/30 or 90/10, but the underlying insight holds. You can also apply the analysis against different metrics, including sales units, gross margin, or on-hand inventory value, depending on what your valuation or inventory turnover analysis requires. For formal appraisal and financial reporting purposes, this classification helps direct accuracy and effort toward the items that most affect your balance sheet.