Value-based methods like ABC analysis answer "which items matter most?" But they don't answer "which items are really moving?" FSN analysis fills that gap. It sorts inventory purely by how often it's used, which makes it good at catching stock that's turning into a problem.

Put simply, FSN analysis sorts inventory into three groups based on how often it moves:

The Three Categories

Fast-moving (F) items are used or sold often, week after week. These are the everyday movers that keep turning over and rarely sit in storage for long.

Slow-moving (S) items are used or sold, but not often. They're not dead stock. But they turn over much more slowly than fast movers, and they tie up space and cash for longer stretches.

Non-moving (N) items haven't been used or sold in a set period, often six months to a year. These are top choices for markdown, bundling, or write-off.

How FSN Analysis Is Calculated

FSN sorting usually looks at two things: the last date an item was issued or sold, and how often it's used over a set period. Items are then placed into the three buckets based on how recently, and how often, they've moved.

Why FSN Analysis Matters

Non-moving stock is easy to miss, since it doesn't cause the clear problems a stockout does. It just sits quietly, taking up space and tying up cash, until someone finally notices. FSN analysis makes this visible on a regular basis, instead of waiting to find it during an annual count.

Using FSN Alongside Other Methods

FSN analysis pairs well with ABC and XYZ analysis. An item might be high-value (A) but non-moving (N). That pairing is a strong signal to find out why it stopped selling — before more money gets tied up ordering more of it.

Key Takeaways

FSN analysis sorts inventory by how often it moves. That makes it a simple way to catch slow-moving and non-moving stock before it becomes dead weight. Paired with value-based methods, it rounds out a fuller picture of what's really happening across a warehouse.

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