ABC-XYZ Inventory Analysis: How to Manage Each Item the Right Way
ABC-XYZ inventory analysis groups items by two questions: how much value each one brings (A, B or C) and how predictable its demand is (X, Y or Z). The result is nine classes, each managed differently — so you protect high-value items, automate predictable ones and stop wasting effort and cash on the rest.
- ABC ranks items by value; XYZ ranks them by how predictable demand is.
- A items are typically about 20% of the range but around 80% of value.
- Each of the nine classes gets its own stock target, review rhythm and automation.
- Re-run the analysis quarterly; items move between classes as markets change.
What is ABC analysis?
ABC analysis ranks items by their annual value — usually sales or consumption value. A items are the vital few: typically around 20% of items producing roughly 80% of value. B items are the middle band. C items are the long tail: many items, little value. The exact cut-offs vary; what matters is applying them consistently.
High value, erratic demand. A planner reviews every order.
High value, steady demand. Tight stock and automatic reorders.
Low value, erratic demand. Make to order or delist.
Low value, steady demand. Bulk orders and rare reviews.
The full method is a 3×3 grid; B and Y items sit between these four corners.
What does XYZ analysis add?
ABC shows importance, not risk. XYZ ranks items by how steady their demand is. X items sell at a fairly constant rate and are easy to forecast. Y items swing with seasons or trends. Z items are erratic — long quiet spells, then sudden orders. Predictability is usually measured by how much weekly or monthly demand varies around its average.
How to run an ABC-XYZ analysis
Process- 01
Gather 12 months of data
Pull sales or usage value and monthly demand for every active item.
- 02
Rank by value (ABC)
Sort items by annual value; mark the top band A, the middle B and the tail C.
- 03
Rank by predictability (XYZ)
Measure how much monthly demand varies around its average; steady is X, erratic is Z.
- 04
Combine into nine classes
Give every item a two-letter class, such as AX or CZ.
- 05
Set a policy per class
Agree service level, safety stock, review frequency and automation for each class.
- 06
Refresh quarterly
Re-run the analysis and act on items that have changed class.
- 01
Gather 12 months of data
Pull sales or usage value and monthly demand for every active item.
- 02
Rank by value (ABC)
Sort items by annual value; mark the top band A, the middle B and the tail C.
- 03
Rank by predictability (XYZ)
Measure how much monthly demand varies around its average; steady is X, erratic is Z.
- 04
Combine into nine classes
Give every item a two-letter class, such as AX or CZ.
- 05
Set a policy per class
Agree service level, safety stock, review frequency and automation for each class.
- 06
Refresh quarterly
Re-run the analysis and act on items that have changed class.
How to manage each ABC-XYZ class
Combine the two and each class gets its own policy. AX items are valuable and predictable: keep them lean and automate replenishment. AZ items are valuable and erratic: watch them closely and let planners decide. CX items can run on simple, infrequent bulk orders. CZ items deserve the hardest question — should you stock them at all, or make them to order?
Common ABC-XYZ mistakes
Teams often run the analysis once and file it. Items move between classes as products age and customers change, so refresh it every quarter. Another trap is classifying only by revenue and ignoring margin or customer importance. Inventory tools such as Owllys Stocki can keep classes updated automatically, so policies change when an item’s behaviour does.
Questions people ask
What percentages should I use for ABC classes?
A common starting point is A for items making up the top 80% of value, B for the next 15% and C for the last 5%. These are conventions, not rules. Adjust them so each class is a manageable size for your team and reflects how your business actually earns money.
How do you measure demand predictability for XYZ?
The usual measure is the coefficient of variation: how much demand varies from period to period, divided by average demand. Low variation means X, moderate means Y and high means Z. Use monthly data for most items, and remove one-off events such as a single bulk order first.
Is ABC-XYZ analysis useful for small businesses?
Yes, often more so. Smaller teams have less time, and ABC-XYZ shows where to spend it. Even a spreadsheet version helps you focus attention on the few items that matter, automate the steady ones and stop over-stocking erratic, low-value lines.