5 NAS drives tracked from $40.00/TB. Prices updated about once a day.
| Buy | Details | ||||||
|---|---|---|---|---|---|---|---|
| $40.00 Lowest $/TB | WD Red Pro 20TB WD201KFGX WD201KFGX | 20TB SATA-6G | CMR | $799.99 | Refurb | Buy on Amazon | |
Part number:WD201KFGX RPM:7200 Cache:512MB Sector:— Workload:550TB/yr DWPD:— Form factor:3.5" Series:WD Red Pro ASIN:B09TBF6GHJ Warranty:5 yr - seller claim, not the maker's This offer, in its own words (the seller's note is verbatim): This offer: sold by ALL4COMPUTERS ----- SIGNATURE REQUIRED ----- · Amazon says Used / Good · ALL4COMPUTERS ----- SIGNATURE REQUIRED -----'s note: 5 YEAR DEALER WARRANTY - 100% SATISFACTION GUARANTEED. | |||||||
| $42.25 ~ 30d avg | WD Red Pro 20TB WD202KFGX WD202KFGX | 20TB SATA-6G | CMR | $845.00 | Refurb | Buy on Amazon | |
Part number:WD202KFGX RPM:7200 Cache:512MB Sector:— Workload:550TB/yr DWPD:— Form factor:3.5" Series:WD Red Pro ASIN:B0DYQH22PW Warranty:5 yr - seller claim, not the maker's This offer, in its own words (the seller's note is verbatim): This offer: sold by Amazon Resale · Amazon says Used / LikeNew · Amazon Resale's note: No item damage observed during inspection. Item will come in original packaging. | |||||||
| $44.00 ~ 30d avg | Seagate IronWolf Pro 20TB NAS ST20000NT001 | 20TB SATA-6G | Not sourced | $879.99 | New | Buy on Amazon | |
Part number:ST20000NT001 RPM:7200 Cache:256MB Sector:512e Workload:300TB/yr DWPD:— Form factor:3.5" Series:IronWolf Pro ASIN:B0B94MF4LP This offer, in its own words (the seller's note is verbatim): This offer: sold by QuickDealStore · Amazon says New / Unknown | |||||||
| $44.61 ~ 30d avg | WD Red Pro 20TB WD202KFGX WD202KFGX | 20TB SATA-6G | CMR | $892.26 | New | Buy on Amazon | |
Part number:WD202KFGX RPM:7200 Cache:512MB Sector:— Workload:550TB/yr DWPD:— Form factor:3.5" Series:WD Red Pro ASIN:B0DYQH22PW This offer, in its own words (the seller's note is verbatim): This offer: sold by Amazon.com · Amazon says New / Unknown | |||||||
| $60.00 ~ 30d avg | WD Red Pro 20TB WD201KFGX WD201KFGX | 20TB SATA-6G | CMR | $1,199.99 | New | Buy on Amazon | |
Part number:WD201KFGX RPM:7200 Cache:512MB Sector:— Workload:550TB/yr DWPD:— Form factor:3.5" Series:WD Red Pro ASIN:B09TBF6GHJ This offer, in its own words (the seller's note is verbatim): This offer: sold by ALL4COMPUTERS ----- SIGNATURE REQUIRED ----- · Amazon says New / Unknown | |||||||
One 20TB NAS drive, in decimal units (1TB = 1,000GB), before file-system and RAID overhead. Each line is a division you can redo; the per-file sizes are our assumptions and say so.
Security cameras, recording continuously: 578 camera-days - 8 cameras for 72 days. The arithmetic: 3.2 Mbps ÷ 8 = 0.4 MB/s × 86,400 s = 34.56 GB per camera-day; 20,000 GB ÷ 34.56 = 578 camera-days. The bitrate is WD's reference figure for one stream (single stream, 1080p, h.265, 25fps), from WD Purple / WD Purple Pro data sheets (footnote 3); the 8-camera count is our example. A camera set to a higher bitrate fills the drive proportionally faster.
Guides for this capacity: best 20TB hard drive · the HDD price forecast · fill a NAS at today's prices
Every listing we track at this size - 5 product pages, including ones with no current offer. Out-of-stock pages carry specs and in-stock alternatives, never a stale price.
We can currently price 5 in-stock 20TB NAS drives from 2 brands (WD and Seagate). The best rate is $40.00 per terabyte, against a $44.00 median across the same capacity - a spread worth noticing, because at this size the gap between the cheapest listing and the middle of the market is real money rather than rounding. The lowest ticket price on a single drive is $800.
The listings split 3 new and 2 recertified, and for a NAS that distinction carries more weight than it does in a desktop. An array runs its drives continuously, so the warranty behind each one is a live concern rather than a formality - new carries the manufacturer's, recertified carries a reseller's, and the discount is the compensation for that difference. Our recertified guidance covers what to check before a drive goes into a pool.
A NAS buyer is choosing a configuration rather than a drive, and the number that decides it is usable capacity after parity. At 20TB per drive that works out as follows, before filesystem overhead and before you leave the headroom a pool needs to stay healthy:
Those totals are drives only. The enclosure, the memory and the drive bays you leave empty for a future expansion are separate costs, and the last of those is the one people forget: filling every bay on day one means the next upgrade is a full replacement rather than an addition. Our RAID planner works through the configurations properly, and replacing drives with larger ones covers the upgrade path when you get there.
All 4 in-stock 20TB drives we can verify use conventional recording, which is what an array needs. Shingled drives overlap their tracks to gain density, and the cost of that is rewrite behaviour that can turn a RAID rebuild into a multi-day event or make it fail outright. At this capacity the stock we track is clean. 1 further listing has no recording technology recorded, and those render as unverified rather than assumed.
Warranty terms in stock run 5 years, and workload ratings run 300 to 550TB per year. That rating is the manufacturer's statement about sustained annual writes, and a NAS serving a household rarely approaches it - it matters when the array is a backup target or a surveillance recorder rather than a media library.
At 20TB the rebuild window is the constraint worth planning around. Resilvering a drive this size takes many hours and often more than a day depending on how busy the pool is, and for the whole of that window a single-parity array has no redundancy left. That is the argument for RAID 6 or RAIDZ2 at this capacity rather than RAID 5, and it is an argument about time exposed rather than about any particular drive being unreliable.
The general rule is that cost per terabyte improves as you go up the ladder until it does not, and where it stops improving moves with the market rather than sitting at a fixed capacity. Comparing the live rate on this page against the neighbouring rungs is the only reliable way to find that point on the day you are buying.
The cheapest in-stock 20TB NAS drive we track works out at $40.00 per terabyte. Prices refresh about once a day, so the table above is the current answer rather than this sentence.
60TB in RAID 5, 40TB in RAID 6, and 40TB in RAID 10, before filesystem overhead. RAID 6 costs you one more drive of capacity and buys the ability to survive a second failure during a rebuild.
Every in-stock 20TB listing we can verify is conventional recording, which is what an array needs. Any shingled drive that appears is badged SMR in the table.
They are widely used for exactly this, but the warranty comes from a reseller rather than the manufacturer, and drives bought together from one batch can age together. Verify on arrival rather than on the listing, and consider mixing sources across the array.
Larger drives usually improve cost per terabyte, but rebuild windows lengthen with capacity, and at 20TB and above that is the constraint rather than the price. RAID 6 or RAIDZ2 rather than single parity is the standard answer at this size.