Seagate · Exos X
ST18000NM003D is Seagate Exos X 18TB SATA-6G. 3 of its 5 segments are defined in Seagate's published documentation and decoded below; the rest are not publicly documented and are marked as such. 2 live listings below.
| 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 |
| 003 | Seagate does not publicly document this segment. | not documented |
| D | Seagate does not publicly document this segment. | not documented |
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.
ST18000NM003D is Seagate Exos X, a 18TB hard drive on SATA-6G.
We currently track 2 live listings against this exact part number, across both new and refurbished stock, which frequently carry different warranty positions even when the part number is identical. 8 sibling part numbers are documented below - these are the numbers most often mistaken for this one, and the table marks which fields actually differ.
| Manufacturer | Seagate |
| Family | Exos X |
| Capacity | 18TB |
| Interface | SATA-6G |
| Product class | HDD |
These are the part numbers most often confused with ST18000NM003D. The differences below come from the same vendor documentation as the decode above - where a field is not documented, the row leaves it blank rather than guessing.
| Part number | Capacity | Interface | Format | |
|---|---|---|---|---|
| ST12000NM002G | 12TB | SAS-12G | in catalogue | |
| ST16000NM001G | 16TB | SATA-6G | in catalogue | |
| ST16000NM002G | 16TB | SAS-12G | in catalogue | |
| ST22000NM001H | 22TB | SATA-6G | in catalogue | |
| ST24000NM000H | 24TB | SATA-6G | in catalogue | |
| ST24000NM002H | 24TB | SATA-6G | in catalogue | |
| ST30000NM004K | 30TB | SATA-6G | in catalogue | |
| ST32000NM004K | 32TB | SATA-6G | in catalogue |
Amber cells differ from ST18000NM003D; grey cells match it.
| Listing | Condition | Pack | $/TB | Price | |
|---|---|---|---|---|---|
| Seagate Exos X20 18TB SATA | Refurb | single | $32.22 | $579.99 | Buy |
| Seagate Exos X20 18TB SATA | New | single | $37.55 | $675.89 | Buy |
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, any part number · ranked by live cost per tb, refreshed every few hours
| Drive | Capacity | Interface | Recording | Condition | $/TB | Price | |
|---|---|---|---|---|---|---|---|
| MDD 18TB SAS 12G 7200RPM Enterprise MDD18TSAS25672E | 18TB | SAS-12G | CMR | NEW | $21.67 | $390 | Buy |
| MDD 18TB SATA 6G 7200RPM NAS MD18TSATA25672NAS | 18TB | SATA-6G | CMR | REFURB | $25.00 | $450 | Buy |
| MDD 18TB SATA 7200RPM NAS MDD18TS25672NAS | 18TB | SATA-6G | CMR | REFURB | $25.56 | $460 | Buy |
| MDD 18TB SATA 7200RPM Enterprise MDD18TSATA25672E | 18TB | SATA-6G | CMR | REFURB | $26.11 | $470 | Buy |
Every 18TB drive we track, ranked by cost per terabyte.
ST18000NM003D is Seagate Exos X 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. The remaining segments are not publicly documented, and we say so rather than repeating a community guess as fact.
Not necessarily, and the part number cannot tell you. Coverage depends on how the individual unit entered the market and whether it was registered, not on its model designation. OEM and gray-market stock reaches the market under manufacturer part numbers regularly and frequently carries no manufacturer warranty at all - some retailers print exactly that on the listing. Check the specific serial with Seagate's own tool, linked in the warranty section on this page.
Both are in the Exos X range. The clearest difference is capacity - 18TB against 12TB. They differ in interface: SATA-6G against SAS-12G, which decides whether the drive fits your controller. The variant table on this page lists every sibling we document with what differs.
We track 2 live listings carrying this part number, shown above with condition and cost per terabyte. Prices come from Amazon US and are re-checked continuously; the buy links go to the live listing because the price can change between our check and your click.
Because more than one organisation names it. The manufacturer assigns a model number describing the product; a server vendor buying it in volume assigns its own spare-part number for its service catalogue; distributors sometimes add another. All identify the same physical drive, which is why one number returns listings that look like a different product. Our part number index explains the pattern per vendor.