The types of inventory are the categories a company's stock falls into, either by production stage (raw materials, work in progress, finished goods, supplies) or by the job it does (safety stock, in transit, cycle, seasonal, consignment, obsolete). These are two separate classifications, and most lists you'll find online blend them into one.
Pulling them apart clears things up, because the same product belongs to both at once: a case of finished mugs on a truck from your supplier is finished goods and in-transit inventory.
Classification 1: by stage
This answers the question "how close is this to being sellable?" It comes from manufacturing:
- Raw materials: inputs that haven't been transformed yet. Fabric, empty bottles, green coffee beans.
- Work in progress (WIP): items that are partway through production. T-shirts that have been cut but not printed.
- Finished goods: products ready to sell as they are.
- MRO (maintenance, repair and operations) or supplies: things you use up to run the operation but never sell. Shipping boxes, tape, labels, spare parts for equipment.
A brand that only resells finished products has almost no raw materials or WIP: its inventory is finished goods plus supplies. If you manufacture or use a contract manufacturer, all four stages count.
Classification 2: by purpose
This answers the question "why am I holding this?" It's the classification that actually drives decisions for an online store:
- Safety stock: the buffer that keeps a sales spike or a late supplier from leaving you out of stock. It has its own formula, which we walk through in how to calculate safety stock.
- In transit: you've paid for it, or it has left the supplier, but it hasn't reached your warehouse. Containers at sea, pallets on the highway, transfers between warehouses.
- Cycle stock: what gets used up between one supplier order and the next. If you reorder monthly, it's what you sell in a month. Don't confuse it with cycle counting, which is a way to count inventory, not a type of it.
- Seasonal or anticipation stock: what you buy ahead of a peak you can see coming: Black Friday, the holidays, back to school, or Mexico's Buen Fin in November.
- Consignment: it sits with whoever sells it, but belongs to the supplier until it's sold. It changes who pays and who carries the risk; we cover it in consignment inventory.
- Obsolete or dead stock: anything that will no longer sell at full price. Last season, a discontinued model, old packaging, an expiration date that's too close.
Some textbooks add more, such as decoupling inventory (stock held between two production steps so one doesn't stall the other). For a brand selling online, these six cover what matters.
All 10 types in one table
| Type | What it is | E-commerce example | Where it lives |
|---|---|---|---|
| Raw materials | Untransformed inputs | Wax and wicks for a candle brand | Workshop or contract manufacturer |
| Work in progress | Partly made | Cut T-shirts, not yet printed | Workshop or contract manufacturer |
| Finished goods | Ready to sell | Boxed tumbler with its barcode | Own warehouse or 3PL |
| MRO / supplies | Used to operate, never sold | Shipping boxes, tape, void fill | Own warehouse or 3PL |
| Safety stock | Buffer against surprises | Extra units of your best seller | Own warehouse or 3PL |
| In transit | Paid for or shipped, not yet received | A container from Asia headed to Manzanillo | On the way |
| Cycle stock | What you sell between orders | The units in your monthly reorder | Own warehouse or 3PL |
| Seasonal | Bought ahead of a peak | Extra stock for Black Friday | On the way, then warehouse or 3PL |
| Consignment | With the seller, owned by the supplier | Your products in a store that pays only for what sells | With the seller |
| Obsolete | No longer sells at full price | Last year's collection | Wherever it is, taking up space |
A 3PL is a third-party logistics provider that stores your goods and fulfills your orders for you. For this table it works the same as your own warehouse: the inventory is still yours.
A note on "accounting inventory types"
If you came here from the accounting side, you've probably run into perpetual and periodic inventory, or valuation methods like weighted average cost. Those are systems for recording and valuing inventory on the books, not types of stock, and they depend on accounting and tax rules worth reviewing with your accountant. We don't cover them in depth here.
Which ones an e-commerce brand should track separately
You don't need to report ten numbers. You need these four kept apart, because each one leads to a different decision:
- Available finished goods. What's in the warehouse, counted, unallocated and in sellable condition. It's the only number your online store should show as stock. If your system adds in what's still on the way, or what's damaged, you'll sell units you can't ship.
- In transit. What you've paid for that hasn't arrived. It tells you when you'll be back in stock, and it's cash that's already gone even though you can't sell it yet.
- Safety stock. Not a separate shelf, but a minimum level per SKU (each variant with its own code: size, color, flavor). Tracking it separately tells you when you've started selling from your buffer.
- Obsolete. What isn't moving. Separating it keeps it from inflating your "available" stock and forces a decision: clear it out, bundle it or write it off. Inventory turnover is how you spot it before it's too late.
Frequently asked questions
What are the types of inventory?
By stage: raw materials, work in progress, finished goods and MRO or supplies. By purpose: safety stock, in transit, cycle, seasonal, consignment and obsolete. Any given product sits in one category from each classification.
What types of inventory does an e-commerce warehouse hold?
Usually finished goods, packing supplies, safety stock and, if nobody's watching, obsolete stock. Raw materials and WIP tend to stay at the workshop or with the contract manufacturer.
Is obsolete inventory the same as shrinkage?
No. Obsolete stock exists and is in good condition, but no longer sells at full price. Shrinkage is inventory the system records that is physically gone or no longer usable.
Keeping available stock apart from what's in transit, from your buffer and from what's stopped moving is far easier when every unit has a recorded location and gets counted often. At Ecommex we manage inventory by location, with cycle counts, for e-commerce brands — see our warehousing service.