ABC inventory analysis: classify annual consumption value

An ABC inventory analysis groups items using a clearly chosen value measure and classification rule. After this exercise, you can save a six-item annual consumption-value worksheet, including a tied-value boundary, without changing stock records or placing an order.

Updated: 18 October 2026.

What will your ABC inventory analysis produce?

Imagine reviewing a small fictional workshop catalogue before deciding what deserves closer attention. Looking only at annual unit counts would favour inexpensive items used frequently. Looking only at unit cost would favour expensive items even when almost none were used. This worksheet combines supplied annual usage with a fixed unit acquisition cost, then ranks the resulting annual consumption values.

Your finished output is a ranked list with individual shares, cumulative shares, an explicit boundary convention and one classification per item. It is not a forecast, profitability assessment, purchase authorization or current stock valuation. All figures below are invented teaching inputs, not supplier quotations or a client case. No inventory application was accessed to produce them.

The low-stock alert guide produces a notification and a staff handoff. That is a different task. An item can have a high annual consumption value while its current stock is ample. Conversely, a low-value item can be essential even when its class is C. Do not turn these labels into automatic operational instructions.

Fix the period, unit and cost basis first

Use the same fictional twelve-month period for all six items. Annual usage is measured in individual pieces. Each cost is a constant teaching input in a single abstract currency. We assume that the supplied usage is complete and nonnegative and that all costs are positive. The exercise does not decide how a real business should value usage when acquisition costs change during the year.

Copy these inputs before calculating. Keep each identifier attached to its quantity and cost. R and S are different items even though their calculated values will match. The original input order is not the final ranking, and replacing identifiers with row numbers would make the later sort harder to audit.

If a real source measures quantity in cartons but cost per piece, resolve that mismatch first. If one item has only a partial year of history, do not silently multiply its usage into a supposedly observed year. Ask the data owner for an appropriate treatment. This small practice card uses a complete period precisely to avoid making that separate forecasting choice.

Multiply, total and sort whole records

Calculate annual consumption value as annual pieces used multiplied by the supplied fixed cost per piece. P gives 50×7=350, Q gives 50×5=250, R gives 20×5=100 and S gives 10×10=100. T gives 15×10=150, while U gives 10×5=50. The total is 350+250+100+100+150+50=1000.

Now sort entire records from highest value to lowest: P, Q, T, R/S, U. T moves ahead of both R and S despite appearing later in the input table. Sorting only the value column would detach the results from their source items. Preserve quantity, cost and identifier together, whether you use paper or a spreadsheet.

The two values of 100 are an intentional tie. At this stage, neither R nor S has a stronger claim to the earlier position. Their annual quantities differ, but annual quantity alone is not the selected ranking measure. You would need an additional, explicitly supplied rule to use quantity as a tie-breaker. Do not add one merely because software requires a display order.

Calculate shares before attaching labels

Divide each value by the total and multiply by 100. P contributes 35%, Q contributes 25%, T contributes 15%, R and S contribute 10% each, and U contributes 5%. These individual shares sum to 100%. Keep that check separate from the number of items: one of six items does not automatically represent one sixth of annual consumption value.

Cumulative share means the value covered from the top of the ranking through the current item or tied block. P reaches 35%, P plus Q reaches 60%, and adding T reaches 75%. R and S together take the running share to 95%; U completes 100%. We will classify the tied pair as a block, so there is no need to pretend that one has precedence.

This table has five displayed ranking rows but still represents six items. The tied block is not a merged product or a new inventory identifier. In the final item register, retain separate R and S records and write B beside each. Combining a display block must not erase the source identities.

Which boundary convention applies to the tied pair?

Our supplied practice rule is explicit: keep equal-value items together, calculate cumulative share after the whole block, then assign A when that share is at most 80%, B when it is above 80% and at most 95%, and C otherwise. Exactly 80% belongs to A; exactly 95% belongs to B. This is a teaching convention, not a universal ABC standard.

P, Q and T finish at 35%, 60% and 75%, so each is A. The R/S block finishes at exactly 95%, so both items are B. U finishes at 100% and is C. The resulting class shares are A=75%, B=20% and C=5%. A is not required to reach exactly 80%; whole items and blocks produce discrete jumps.

To see why the rule matters, consider an incorrect alphabetical split. R could be placed first, taking the cumulative share from 75% to 85%, followed by S at 95%. Another convention might assign a crossing item to the earlier class. That could make otherwise equal items receive different labels. Do not mix conventions or claim one result without stating the rule that generated it.

What should stop a final classification?

A missing cost is not zero. If any consumption value is unresolved, the total and every percentage can also change. Keep partial arithmetic as a draft, but hold the final catalogue classification. Excluding the unknown item and calling the remaining subtotal the complete total would conceal the missing evidence rather than solve it.

If all supplied values are zero, dividing by the grand total is undefined. This worksheet would have no value-share classification to report. If quantities are negative because a source includes returns or corrections, stop and ask how that source defines usage. The current exercise does not provide a netting policy, so one should not be invented to force the formula to work.

A classified list also does not establish physical availability. The stock-count discrepancy card compares book and observed quantities. The running-balance audit checks movements in sequence. Neither result is interchangeable with annual consumption-value ranking, and none automatically authorizes a purchase.

Save a worksheet another person can reproduce

On Windows, search Start for Notepad, open the application and create a new document headed “ABC V1, fictional annual consumption values.” Include the six original inputs, six products, total, ranking, individual shares, block shares and exact classification convention. Finish with a separate item-level result: P A, Q A, T A, R B, S B, U C. That preserves all six identities while showing why the tied pair stays together.

V1 | fictional year | pieces × fixed unit acquisition cost
Values: P350 Q250 R100 S100 T150 U50; total1000
Ranking: P,Q,T,{R,S},U
Cumulative after blocks: 35,60,75,95,100%
Rule: equal values together; post-block ≤80 A; ≤95 B; else C
Final: P A; Q A; T A; R B; S B; U C
No purchasing or stock-record changes performed.

Press Ctrl+S, choose Documents and save as abc-consumption-V1.txt. Close the editor. In File Explorer, open Documents and double-click the saved file; check that both R and S remain B. The document-version guide explains why a decision needs a specific input version. If the cost basis or threshold rule changes, retain V1 and record a new version rather than silently editing the old conclusion.

Allowing fifteen minutes for this small exercise is a planning suggestion, not a measured participant result. In an earlier published reflection, Anar described delaying his own projects while pursuing perfection. The limited lesson applied here is to finish one inspectable worksheet; it is not evidence that he ran ABC classification for a customer or measured savings from it.

Keep the source definitions and business decision separate

Zoho's opened guide describes annual consumption-value classification. Shopify's opened help page documents a different revenue-based grading approach and explicitly excludes item cost from that grading calculation. The two sources demonstrate why the ranking basis must be named; this worksheet is not a reproduction of a Shopify report. The fictional inputs and tied-block convention belong to this exercise.

Before applying real labels operationally, give the worksheet owner a question: what additional evidence would justify different review effort? A low-value spare might still interrupt production when missing. The class itself contains no supplier lead time, shortage consequence or safety evidence. Keep those questions visible instead of presenting C as permission to ignore an item.

The new-commitment stock check asks whether competing requests fit limited uncommitted supply under a supplied priority rule. Our output does not answer that question. It gives an auditable classification of annual consumption values, leaving replenishment, commitments and service promises for their own decisions.