{"id":45487,"date":"2026-07-03T15:19:34","date_gmt":"2026-07-03T09:49:34","guid":{"rendered":"https:\/\/www.verdantis.com\/?p=45487"},"modified":"2026-07-03T20:07:03","modified_gmt":"2026-07-03T14:37:03","slug":"tipos-de-clasificacion-de-existencias","status":"publish","type":"post","link":"https:\/\/www.verdantis.com\/es\/tipos-de-clasificacion-de-existencias\/","title":{"rendered":"Tipos de inventario: una gu\u00eda de clasificaci\u00f3n para profesionales"},"content":{"rendered":"
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Ask ten supply chain professionals for the types of inventory and most will recite the same four items: raw materials, work in progress, finished goods, MRO. That list is not wrong, it is incomplete.<\/p>\n

Inventory classification is not one taxonomy. It is at least seven independent lenses, and each one answers a different operational question.<\/p>\n

Using the wrong lens for a decision, such as applying a value-based ABC ranking to a criticality decision, is one of the most common and costly mistakes in inventory management.<\/p>\n

This guide walks through each lens, a named example for every category inside it, and the formula, explained practically, behind it.<\/p>\n

If you manage spare parts specifically and want the prioritization mechanics (ABC, VED, FSN, XYZ), that detailed model lives in our spare parts prioritization framework<\/a>.<\/p>\n

This article is the map that tells you when that framework is the right tool to reach for, and when a different lens fits better.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Why Inventory Classification Is Not One Thing<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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The confusion starts with the question itself. "What are the types of inventory" implies a single correct answer. In practice, at least seven classification lenses coexist, each built to serve a different decision-maker.<\/p>\n

A finance team classifying inventory for balance sheet valuation needs a different lens than a maintenance planner deciding how many spares to stock, and a different lens again from a procurement lead assessing supplier risk.<\/p>\n

The table below is the organizing structure for the rest of this article.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Lens<\/th>Question It Answers<\/th>Qui\u00e9n lo utiliza<\/th>Example Decision<\/th><\/tr>
Functional<\/span><\/td>Why does this unit of stock exist?<\/td>Inventory planners<\/td>Setting reorder policy<\/td><\/tr>
Value-Chain Position<\/span><\/td>Where does this sit between raw input and sale?<\/td>Finance, ERP teams<\/td>Valuation and accounting treatment<\/td><\/tr>
Patr\u00f3n de demanda<\/span><\/td>How predictable is consumption over time?<\/td>Demand planners<\/td>Choosing a forecasting method<\/td><\/tr>
Ownership and Custody<\/span><\/td>Who owns it and who holds the risk?<\/td>Procurement, finance<\/td>Deciding stocking location and terms<\/td><\/tr>
Physical and Handling<\/span><\/td>What does storage or movement require?<\/td>Warehouse operations<\/td>Storage design and safety compliance<\/td><\/tr>
Obsolescence and Utilization<\/span><\/td>Is this stock still active or fading out?<\/td>Inventory analysts<\/td>Write-down and disposition timing<\/td><\/tr>
Strategic Sourcing Risk<\/span><\/td>How exposed is supply, independent of value?<\/td>Category managers<\/td>Assessing supply exposure<\/td><\/tr><\/table><\/div>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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With that framing in place, each of the following sections works through one lens in depth, with a named example for every single category and the formula, explained practically, behind it.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Classification by Function: Why the Inventory Exists<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Every unit sitting in a warehouse is there for a reason, and that reason has a name. Functional classification breaks total on-hand quantity into the operational role each portion plays.<\/p>\n

Holding too little of any category risks a stockout with its own specific cause. Holding too much ties up working capital for no operational benefit, and the cost driver behind each type differs, which is why lumping them into one "total inventory" number hides more than it reveals.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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1. Cycle Stock<\/div>
The portion consumed between two scheduled replenishments under normal, predictable demand.<\/div>
Por ejemplo:<\/strong> The deep-groove ball bearings and pleated air filters a plant reorders every cycle to cover normal, predictable consumption.<\/div><\/div>
2. Safety Stock<\/div>
A buffer held against demand spikes or supplier delays beyond the expected average.<\/div>
Por ejemplo:<\/strong> Extra centrifugal pump mechanical seals held specifically because the supplier's lead time varies by several weeks.<\/div><\/div>
3. Anticipation Stock<\/div>
Built ahead of a known future event: a seasonal peak, a planned shutdown, a price increase.<\/div>
Por ejemplo:<\/strong> PTFE gaskets and oil filters stockpiled ahead of a planned turnaround, before the plant shuts down for maintenance.<\/div><\/div>
4. Pipeline Stock<\/div>
In transit between a supplier, a plant, or a distribution point, not yet available to use.<\/div>
Por ejemplo:<\/strong> A replacement gearbox already shipped from an overseas OEM but still weeks from arrival at the plant.<\/div><\/div>
5. Decoupling Stock<\/div>
Held between production stages so one stage's schedule does not force-stop another.<\/div>
Por ejemplo:<\/strong> A buffer of machined pump shafts held between two production stages so a short upstream stoppage does not halt final assembly.<\/div><\/div>
6. Speculative Stock<\/div>
Bought ahead of need to hedge against expected price increases or supply shortages.<\/div>
Por ejemplo:<\/strong> Extra copper wiring purchased ahead of an anticipated price spike or a known supply shortage.<\/div>
Note:<\/strong> This tactic is most common in electrical and utility-heavy industries, where commodity price swings hit hardest.<\/div><\/div><\/div>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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A Worked Example: Decomposing One SKU<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Take a single spare part with 500 units on hand. Reduce a fast-turning cycle stock quantity and you save carrying cost with little risk. Reduce the safety stock behind an unreliable supplier without addressing the lead time variability, and you have just increased your stockout probability.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Sizing the Safety Stock Component<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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In the formulas below, d is average demand per period, L is average lead time, sigma-d is the standard deviation of demand, sigma-L is the standard deviation of lead time, Z is the service-level factor from the standard normal distribution, and Q is the order quantity.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Reorder Point (ROP)<\/div>
ROP = (d × L) + Safety stock<\/div>
In practice: order the moment stock hits this number, so the replacement arrives right as safety stock alone would otherwise run out.<\/div><\/div>
Safety Stock (Normal Approximation)<\/div>
SS = Z × √(L × σd² + d² × σL²)<\/div>
Worked example: a mill averaging 130 units a week with a demand deviation of 28 units needs about 56 units of safety stock (Z ≈ 2) to hit a 98% service level. The relationship is not linear: pushing from a 95% to a 99% service level (Z from 1.65 to 2.33) requires disproportionately more buffer for the same variability. Source: ASCM<\/a><\/div><\/div>
Average Cycle Stock<\/div>
Cycle stock ≈ Q ÷ 2<\/div>
In practice: ordering 600 units at a time leaves roughly 300 units sitting in cycle stock on average between deliveries.<\/div><\/div>
Pipeline Stock (Little's Law)<\/div>
Pipeline stock = d × L<\/div>
Worked example: a warehouse holding 10,000 units against 15,000 units sold per month holds about two-thirds of a month's stock at any time, the same math applied to an in-transit spare. Source: AllAboutLean<\/a><\/div><\/div><\/div>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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A blanket "hold more safety stock everywhere" policy wastes capital on low-risk items precisely because of that non-linearity, higher service targets should be reserved for parts where a stockout is genuinely expensive.<\/p>\n

Recalculating the split whenever lead time, demand variability, or the service-level target changes is what keeps the functional classification current.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Classification by Position in the Value Chain<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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This is the classification most ERP and accounting systems are structured around, because valuation treatment differs by stage of production.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Raw Materials<\/div>
Unprocessed inputs purchased from suppliers, not yet committed to a specific production run.<\/div>
Por ejemplo:<\/strong> A coil of hot-rolled steel sheet waiting to be cut, or a stockpile of iron ore waiting to be processed.<\/div><\/div>
Work-in-Process<\/div>
Partially completed goods somewhere between raw input and a sellable finished item.<\/div>
Por ejemplo:<\/strong> A partially machined pump shaft sitting between two operations on the production line.<\/div><\/div>
Finished Goods<\/div>
Completed products ready for sale, the inventory category most visible to the balance sheet.<\/div>
Por ejemplo:<\/strong> A fully assembled, tested, and packaged centrifugal pump ready to ship to a customer.<\/div><\/div>
MRO \/ Indirect<\/div>
Maintenance, repair, and operating items that support production without becoming part of the product.<\/div>
Por ejemplo:<\/strong> The bearings, gaskets, and lubricants that keep a production line running.<\/div>
Note:<\/strong> Asset-heavy industries such as oil and gas, mining, and manufacturing devote the most operational effort to managing this category, since it can represent a large share of total inventory value without ever appearing in the finished product.<\/div><\/div><\/div>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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MRO inventory sits apart from the other three because it never becomes the product a customer buys. It exists to keep the equipment that makes the product running, which is why it needs a materially different stocking and prioritization approach than raw materials or finished goods.<\/p>\n

If your organization is trying to right-size that category specifically, our guide to MRO stocking policy and reorder planning<\/a> picks up where this section leaves off.<\/p>\n

Getting the classification right in the first place also depends on clean, deduplicated material records<\/a>, since a duplicate item master entry can make the same part look like it belongs to two different value-chain stages at once.<\/p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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\n\t\t\t\t\tSee These Classification Lenses Applied to Your Own Parts Data<\/span>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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See how an AI-native platform applies these classification lenses to your own spare parts inventory.<\/p><\/span>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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