ABC Analysis for Inventory:
How to Classify Your SKUs
ABC analysis ranks your SKUs by how much value they drive, so your attention, safety stock, and service levels go where they earn the most. The 80/20 method, a worked classification table, per-class policies, and the XYZ extension.
By Replenagise · Updated 11 July 2026 · 6 min read
What ABC analysis is — the 80/20 of your catalog
ABC analysis applies the Pareto principle to inventory: a small share of SKUs drives most of your revenue. Rank every SKU by annual sales value, then cut the list into classes — typically A = the top SKUs producing ~80% of value (often ~20% of SKUs), B = the next ~15% of value, C = the long tail producing the last ~5% (often half your catalog).
The point is not the labels; it is permission to treat products differently. A-class SKUs justify tight forecasting, high service levels, and weekly attention. C-class SKUs justify simple rules and bulk decisions. Treating all SKUs the same means over-managing the tail and under-managing the head.
How to run it: four steps
1. Rank by annual value
For each SKU: units sold × cost (or revenue) over the last 12 months. Sort descending. Use stockout-adjusted sales so an A-class SKU that spent a quarter out of stock does not masquerade as a B.
2. Cut into classes
Walk down the ranked list accumulating value: SKUs up to 80% of the total → A; to 95% → B; the rest → C. A 1,000-SKU catalog might land at 180 A-SKUs, 320 Bs, and 500 Cs.
3. Set policies per class
A: 97–99% service level, generous safety stock, weekly review, never stock out. B: 92–95%, standard buffers, fortnightly review. C: 85–90%, minimal buffers, order to simple rules, consider culling the worst.
4. Re-classify on a schedule
Products migrate — last year’s hero fades, a sleeper takes off. Re-run the analysis quarterly (or continuously in software) so policies follow the product, not its reputation.
ABC-XYZ: adding predictability to value
Value is only half the picture — variability is the other. The XYZ extension classes each SKU by demand stability: X = steady and easy to forecast, Y = variable (often seasonal), Z = erratic. Cross the two and you get a 9-cell grid that actually sets policy: AX (high value, steady) runs almost hands-off on automation; AZ (high value, erratic) is where your planner’s time belongs; CZ (low value, erratic) is the cell to buy to order — or delist.
Replenagise runs ABC and ABC-XYZ classification automatically from live Shopify and Linnworks sales, keeps classes current as demand shifts, and ties service-level policies to each class — so safety stock and reorder points inherit the right aggressiveness per SKU without a quarterly spreadsheet ritual.
Where the classes lead: C-class laggards become dead stock if ignored, class health shows up in the inventory turnover ratio, and inventory replenishment software turns each class’s policy into automatic reorders.
ABC Analysis — FAQs
What is ABC analysis in inventory management?
A classification method that ranks SKUs by annual sales value and splits them into classes: A (the small group driving ~80% of value), B (the next ~15%), and C (the long tail at ~5%). Each class then gets its own service level, safety stock, and review cadence.
How do you calculate ABC classification?
Multiply each SKU’s annual units by cost or price, sort descending, and accumulate: SKUs up to 80% of total value are A, up to 95% are B, the remainder C. The thresholds are conventions — adjust to your catalog’s shape.
What is ABC-XYZ analysis?
ABC crossed with a demand-stability dimension: X = steady demand, Y = variable/seasonal, Z = erratic. The 3×3 grid sets planning policy — automate the stable high-value cells, focus human attention on high-value erratic SKUs, and simplify or cull the low-value erratic tail.
Can ABC analysis be automated?
Yes. Replenagise classifies your catalog continuously from live sales data, re-classes SKUs as demand shifts, and links service-level policies to each class — so the classification actually drives safety stock and reorder points instead of living in a slide deck.
Classification That Sets Real Policy
Automatic ABC-XYZ classes from live sales, tied to service levels, safety stock, and reorder points — for Shopify and Linnworks.