Seagate · Exos X18 · 512e
ST18000NM000J is Seagate Exos X18 18TB SATA-6G. 3 of its 5 segments are defined in Seagate's published documentation and decoded below; for the rest we have not found a defining document, and they are marked as such. No live listings right now - the reference material below still applies.
| Segment | What it means | Source |
|---|---|---|
| ST | Seagate product prefix. | Seagate |
| 18000 | Capacity field. 18000 denotes 18TB of formatted capacity. | Seagate |
| NM | Enterprise nearline family (Exos and its OEM equivalents). | Seagate |
| 000 | Not sourced - we have not found a Seagate document defining this segment. | Not sourced |
| J | Not sourced - we have not found a Seagate document defining this segment. | Not sourced |
We decode only what the manufacturer documents. There is a large body of community knowledge about the undocumented segments above, much of it probably right, and none of it published by Seagate - so it does not appear in this table. A reading nobody can check does not belong in a column headed “what it means”. Grammar reference: Seagate - product part-number and model-number decoding.
ST18000NM000J is Seagate Exos X18, a 18TB hard drive on SATA-6G. It uses the 512e sector format, which decides whether it will drop into an array or controller expecting the other one.
We hold no live listing against this exact part number at the moment. We document no sibling variants for this part number.
| Manufacturer | Seagate |
| Family | Exos X18 |
| Capacity | 18TB |
| Interface | SATA-6G |
| Sector format | 512e |
| Product class | HDD |
No seller we track has ST18000NM000J in stock right now. That describes today's listings only - it says nothing about whether the model is discontinued. We are not going to fill this space with something else and call it a match. The decode, specifications and sibling table above are the reference answer for this part number and remain accurate whether or not anyone is selling one today. If you need the capacity rather than this specific part, the alternatives below are what is actually buyable.
A manufacturer part number does not imply a manufacturer warranty, and this is where part-number buyers lose the most money. OEM stock, integrator pulls and gray-market units all reach the market under the maker's own numbering. Retailers selling them sometimes state plainly that the manufacturer warranty is none; others simply do not mention it, which is not the same as it being covered.
Coverage attaches to the individual unit and its serial number, not to the part number. That means the only reliable answer comes from the manufacturer, about the specific drive you are being sold.
Ask the seller for the serial number before purchase, then enter it in Seagate warranty checker. We link the tool rather than showing a result here, because the answer depends on the individual drive and only Seagate can give it.
A seller warranty is a different promise from a different company. What each warranty tier actually covers · Verify on arrival
4 in-stock listings · same capacity and interface, any part number · ranked by live cost per tb, refreshed about once a day
| Drive | Capacity | Interface | Recording | Condition | $/TB | Price | |
|---|---|---|---|---|---|---|---|
| WD Purple 18TB WD180PURZ WD180PURZ | 18TB | SATA-6G | — | REFURB This offer: sold by The last frontier · Amazon says Used / LikeNew | $28.33 | $510 | Buy Now |
| MDD 18TB SATA 7200RPM NAS MDD18TS25672NAS | 18TB | SATA-6G | — | REFURB This offer: sold by goHardDrive · Amazon says New / New · title says Renewed | $28.33 | $510 | Buy Now |
| WD DC HC550 18TB SATA 512MB Enterprise WUH721818ALE6L4 | 18TB | SATA-6G | EPMR | REFURB This offer: sold by Dealforless · Amazon says Used / Good | $28.89 | $520 | Buy Now |
| WD Red Pro 18TB WD181KFGX WD181KFGX | 18TB | SATA-6G | CMR | REFURB This offer: sold by PrimeDrive · Amazon says New / New · title says Renewed | $29.88 | $538 | Buy Now |
Every 18TB drive we track, ranked by cost per terabyte.
ST18000NM000J is Seagate Exos X18 18TB SATA-6G. 3 of its 5 segments are defined in Seagate's own published documentation - the decode table on this page shows each one with the document that defines it. For the remaining segments we have not found a defining document, and we say so rather than repeating a community guess as fact.
The part number cannot tell you - coverage follows how the unit entered the market, not its designation. We track no live listing for ST18000NM000J right now, so there is no condition evidence to report either way. Check the specific serial with Seagate's own tool, linked in the warranty section on this page.
We hold no live listing for this part number right now. That is the honest state rather than a broken page - this remains the reference answer for what ST18000NM000J is, how it decodes and which siblings it is confused with. The alternatives section below shows what is currently buyable at the same capacity.