Segment items by annual usage value

An inventory team cannot count every item daily with equal effort. ABC analysis helps direct control toward items representing the highest annual usage value. It is one decision lens, not a permanent statement about an item's quality or a customer's importance. Calculate each item's usage value as quantity used over a consistent period multiplied by the agreed unit value for comparison. Use a full year where possible, and separate price or unit-of-measure changes. Do not put shelf balance into this formula: unsold stock is not high usage. Sum values, rank items from highest to lowest, divide each by the total, and accumulate the resulting shares down the ranking. Choose category boundaries according to team capacity and control purpose, and record them before sorting; an illustrative percentage is not a universal rule. If total usage value is zero, percentages cannot be computed; repair the movement history or use another criterion. The ranking can guide count frequency, variance investigation and forecast review because a one-unit error on a costly item may tie up significant working capital. It does not remove professional exceptions. A low-value component could stop production, while a lot-tracked material may require stronger control despite being in category C. Add a separate criticality, lead-time or storage-risk field; do not hide such judgments in the value calculation. An A item does not necessarily have the highest stockout rate. ABC measures usage value as defined, not interruption probability. Make the output operational: assign review frequency, adjustment approval level and a way to handle poor data to each category. Check that all items use the same observation period; comparing a full year for one with three months for a new item is misleading. Mark a new item as having insufficient history rather than confidently labeling it C. Revisit categories when demand mix changes, but retain the calculation version supporting past count decisions. Finally, ABC is only as reliable as its source movements. If issues are recorded inaccurately, a neat ranking directs effort to the wrong place. Clean units, period and movement history first, then allocate attention with an explicit exception path for low-value items that matter greatly to service or safety.

When implementing ABC in a spreadsheet, keep auditable columns: stable item ID, period usage quantity, comparison unit value, product, share of total, cumulative share, class, then an independent criticality flag. Sort on the product, not unit price. An expensive item used once can rank below a moderate-price item used frequently. Define how equal-value items are handled at a class boundary. Do not split them arbitrarily because alphabetical order changed their position; keep them together or document a second criterion without claiming the value ratio dictates a unique answer. Translate classes into actual count work. If A is counted weekly and contains forty items, that is forty counts a week before critical exceptions. Check team capacity. If it is inadequate, revise boundaries or frequency with an explicit risk trade-off rather than approving a plan nobody can execute. Category C is not a synonym for neglect: it still needs reliable movement recording and a less frequent count, with a clear exception for high service impact. In the example, if U's use doubled from 300 to 600 pieces at value five, its usage value becomes 3,000 and total becomes 10,000. Ranking changes to S 5,000, U 3,000, T 2,000, shares 50%, 30% and 20%. U moved to second because of observed usage, not because its criticality flag altered the calculation. Revisit control frequency from both independent dimensions rather than silently changing class limits to obtain a desired outcome.