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Best 20 TB Hard Drives

20 TB drives sit at the high end of mainstream capacity, offering maximum density for builds where every bay slot counts. These are almost exclusively helium-sealed enterprise or NAS models, delivering excellent sustained throughput and power efficiency per terabyte. If you are building dense storage — whether a JBOD shelf, a high-capacity NAS, or a Plex archive — 20 TB drives let you pack more usable storage into fewer slots.

Why 20 TB?

20 TB drives deliver roughly 11% more capacity than 18 TB at a modest price premium — but check the per-TB cost carefully, as 18 TB sometimes wins on value. The sweet spot is when 20 TB models are on sale or when bay slots are your limiting factor. Four 20 TB drives in RAID 5 give you ~60 TB usable.

Prices updated hourly from Amazon US and UK. All links go directly to the retailer. Details.

Best Value 20 TB Drives

All new 20 TB hard drives ranked by price per terabyte across brands and product lines.

£17.00/TB New

WD 20TB Elements External Hard Drive, Desktop HDD storage, USB 3.0 compatible, Fast Transfer rates, Plug-and-play storage for all your pictures, videos, music and documents, Black

20 TB External 3.5" USB
£339.99 Amazon UK· 59m
£18.51/TB New

WD Elements 20TB Desktop USB 3.0 External Hard Drive with the SanDisk Ultra 256GB USB 3.0 Flash Drive

20 TB External 3.5" USB
£370.17 Amazon UK· 3h
$22.00/TB New

WD 20TB Elements Desktop External Hard Drive, USB 3.0 drive for plug-and-play storage - WDBWLG0200HBK-NESN

20 TB External 3.5" USB
$439.99 Amazon US· 1h 57m
$22.00/TB New

Seagate Expansion 20TB External Hard Drive HDD - USB 3.0, with Rescue Data Recovery Services (STKP20000400)

20 TB External 3.5" USB
$439.99 Amazon US· 1h 53m
£22.00/TB New

Seagate Expansion Desktop 20TB, External Hard Drive, USB 3.0, Data Rescue Services (STKP20000400)

20 TB External 3.5" USB
£439.99 Amazon UK· 6m
$22.00/TB New

Seagate Skyhawk AI 20TB Video Internal Hard Drive HDD – 3.5 Inch SATA 6Gb/s 512MB Cache for DVR NVR Security Camera System with in-House Rescue Services (ST20000VE003)

20 TB Internal 3.5" SATA
$439.99 Amazon US· 1d 18h
£24.00/TB New

Toshiba N300 20TB NAS 3.5-Inch Internal Hard Drive - CMR SATA 6 GB/s 7200 RPM 512 MB Cache - HDWG62AXZSTA

20 TB Internal 3.5" SATA
£479.99 Amazon UK· 2h 10m
£24.00/TB New

Toshiba N300 internal hard drive 20 TB 7200 RPM 512 MB 3.5" Serial ATA III

20 TB Internal 3.5" SATA
£479.99 Amazon UK· 1h 30m

Enterprise 20 TB Drives

Exos and Ultrastar 20 TB models for datacenter and server workloads. Maximum density with 24/7 endurance ratings.

$25.00/TB New

Seagate Exos X24 3.5" Internal Hard Drive - 20TB, Single, SATA III 6 Gb/s

20 TB Internal 3.5" SATA
$499.99 Amazon US· 5h 37m
£33.10/TB New

Seagate Exos X24 ST20000NM007H - 20TB

20 TB Internal 3.5" SAS
£662.00 Amazon UK· 2h 11m
$34.70/TB New

Seagate Exos X20 ST20000NM000D 20 TB Hard Drive - Internal - SATA (SATA/600) - Conventional Magnetic Recording (CMR) Method - Storage System, Video Surveillance System Device Supported - 7200rpm - 285

20 TB Internal 2.5" SATA
$694.00 Amazon US· 1h 54m
$40.76/TB New

Seagate Exos X20 ST20000NM007D 20TB 7.2K RPM SATA 6Gb/s 3.5in Hard Drive

20 TB Internal 3.5" SATA
$815.13 Amazon US· 23h 58m

NAS 20 TB Drives

IronWolf and WD Red 20 TB models for high-capacity NAS builds. NAS firmware with vibration tolerance and RAID-optimised error recovery.

£34.27/TB New

WD Red Pro 20TB NAS 3.5" Internal Hard Drive - 7200 RPM Class, SATA 6 Gb/s, CMR Recording Technology, 512MB Cache

20 TB Internal 3.5" SATA
£685.35 Amazon UK· 44m
£35.89/TB New

WD Red Pro 20TB NAS 3.5" Internal Hard Drive - 7200 RPM, SATA 6 Gb/s, CMR, 512MB Cache

20 TB Internal 3.5" SATA
£717.78 Amazon UK· 1h 19m
£37.00/TB New

Seagate IronWolf Pro 20TB, Enterprise Internal NAS HDD, CMR 3.5 Inch, SATA 6GB/s, 7.200 RPM, 256MB Cache for RAID NAS, Rescue Services - Frustration Free Packaging (ST20000NTZ01)

20 TB Internal 3.5" SATA
£739.99 Amazon UK· 3h 59m

Refurbished 20 TB Drives

Recertified 20 TB enterprise pulls at significant discounts. High-density storage for homelabs, archives, and Plex libraries on a budget.

£16.49/TB Used

WD 20TB Elements External Hard Drive, Desktop HDD storage, USB 3.0 compatible, Fast Transfer rates, Plug-and-play storage for all your pictures, videos, music and documents, Black

20 TB External 3.5" USB
£329.79 Amazon UK· 59m
£17.80/TB Used

Seagate Expansion Desktop 20TB, External Hard Drive, USB 3.0, Data Rescue Services (STKP20000400)

20 TB External 3.5" USB
£356.04 Amazon UK· 6m
$19.98/TB Used

WD 20TB Elements Desktop External Hard Drive, USB 3.0 drive for plug-and-play storage - WDBWLG0200HBK-NESN

20 TB External 3.5" USB
$399.50 Amazon US· 1h 57m
£22.87/TB Used

Seagate IronWolf Pro 20TB, Enterprise Internal NAS HDD, CMR 3.5 Inch, SATA 6GB/s, 7.200 RPM, 256MB Cache for RAID NAS, Rescue Services - Frustration Free Packaging (ST20000NTZ01)

20 TB Internal 3.5" SATA
£457.36 Amazon UK· 3h 59m
$23.85/TB Used

Seagate Exos 20TB 7.2K RPM SATA 6Gb/s 3.5in Enterprise HDD ST20000NM002C

20 TB Internal 3.5" SATA
$477.00 Amazon US· 2d 11h
$24.00/TB Used

Avolusion PRO-H1 20TB 7200RPM USB 3.2 Gen2 (10Gbps) External Hard Drive (for Windows or MacOS Desktop PC/Laptop) (Renewed)

20 TB External 3.5" USB
$479.99 Amazon US· 2d 4h
$24.50/TB Used

Avolusion PRO-X USB 3.0 External Hard Drive for WindowsOS Desktop PC/Laptop - (20TB) (Renewed)

20 TB External 3.5" USB
$489.99 Amazon US· 2d 4h
$24.50/TB Used

Avolusion PRO-T5 Series USB 3.0 External Hard Drive for WindowsOS Desktop PC/Laptop (White) - 2 Year Warranty (20TB) (Renewed)

20 TB External 3.5" USB
$489.99 Amazon US· 19h 36m