ABC Analysis Explained
5 min read
By
TranZact Solutions Team
· Published
TL;DR: ABC analysis ranks inventory by consumption value, unit cost times annual usage, sorting SKUs into A, B, and C tiers. A small group of SKUs, the A-tier, usually accounts for most of the total inventory value. Control effort should concentrate there, not spread evenly across every item.
A factory can have thousands of SKUs but the bulk of its inventory spend usually sits in a small fraction of them. ABC analysis is how you find that fraction.
What Is ABC Analysis?
ABC analysis is an inventory classification technique that ranks items by their annual consumption value, calculated as unit cost multiplied by usage quantity. It then groups them into three tiers based on their share of total spend.
A-category items are the few SKUs that account for most of the consumption value. B-category sits in the middle. C-category is the many remaining SKUs that together account for a small share of spend.
The technique is a purchasing and inventory-control prioritization tool, not a criticality measure. A cheap, high-volume fastener can be C-category by value but still stop the line if it runs out. That is why ABC gets paired with VED for operationally critical items.
ABC vs VED Analysis
Basis: ABC ranks items by consumption value, price times usage; VED ranks items by operational criticality, regardless of cost.
Goal: ABC tells you where to focus cost control and ordering discipline; VED tells you where stock-outs simply cannot happen.
Overlap: a C-category item under ABC can be Vital under VED, a cheap part with no substitute. ABC alone would misprioritize exactly this combination.
Best use: use ABC to decide where tighter reorder discipline pays off financially; use VED to decide where availability matters regardless of cost.
Combined approach: many manufacturers cross-tabulate ABC and VED, AV, BV, CV, to prioritize both cost and criticality together.
ABC tiers at a glance
Tier | Share of value | |
|---|---|---|
A tier | Largest share | Tight reorder points, frequent review |
B tier | Middle share | Moderate, periodic review |
C tier | Smallest share | Simple, less frequent reordering |
How ABC Classification Works
Calculating ABC classification comes down to a few steps:
Calculate annual consumption value. Multiply each item’s unit cost by its annual usage quantity to get its total value contribution.
Rank items by value, highest to lowest. Sort the full SKU list so the biggest spend items sit at the top.
Apply cumulative percentage cutoffs. Items making up the largest block of cumulative value become A, the next block becomes B, and the remaining SKUs become C.
Set control policy by tier, not per SKU. A gets tight reorder points and frequent review, C gets simplified, less frequent reordering; review effort matches the payoff.
Common ABC Analysis Mistakes
Where ABC classification typically goes wrong:
Using unit price instead of total consumption value. A high-priced item bought rarely can rank lower than a cheap item bought constantly; ranking by price alone misses this.
Treating C-category as low priority for everything. C-category is low priority for cost control, not necessarily for availability; a Vital, low-cost spare still needs safety stock.
Recalculating too rarely. Usage patterns shift with demand and seasonality; an ABC classification from 18 months ago can misallocate control effort today.
Applying one reorder policy across all SKUs regardless of category. The entire point of ABC is differentiated control; running every item through the same review cycle defeats it.
Ignoring lead time in the classification. A C-category item with a long, unreliable lead time can still need safety stock despite its low value ranking.
Do you actually know which few SKUs are eating most of your inventory spend, or is it a guess?
An ABC classification is only as good as the usage and cost data behind it. If your system stock doesn’t match the floor, your tiers drift too.
How TranZact Supports Inventory Prioritization
TranZact is a manufacturing AI software which ensures your system stock and physical stock always match.
Its inventory management features include stock in, issue, bin card, multi-store, reorder and AI stock alerts, plus inventory ageing and valuation. Inventory management comes with the Scale and Dominate plans, not the Free plan.
Once you’ve built your own ABC tiers, each tier needs its own reorder levels. Those levels only work on stock numbers your team trusts, not a spreadsheet nobody has updated since the last audit.
FAQs
What does ABC stand for in inventory management?
A, B, and C are simply category labels, not an acronym. They rank items by consumption value: A is high-value, B is moderate, C is low-value but usually high in count.
How do you calculate ABC classification?
Multiply each item’s unit cost by its annual usage quantity to get consumption value. Rank all items from highest to lowest, then apply cumulative percentage cutoffs. The top block of value becomes A, the next block becomes B, and the rest becomes C.
What percentage of items are usually A-category?
A small share of SKUs usually accounts for most of the consumption value. This follows the general pattern known as the Pareto principle. The exact split varies by business.
What is the difference between ABC and VED analysis?
ABC ranks by consumption value, cost times usage. VED ranks by operational criticality regardless of cost. A low-value item can be Vital under VED but C-category under ABC, which is why many manufacturers use both.
How often should ABC classification be updated?
At least annually, and more often if usage patterns shift significantly, seasonal demand changes, or new SKUs get introduced. A stale ABC classification misallocates control effort to the wrong items.
Want stock data you can trust before you set your ABC tiers? See how TranZact handles it for your items.
