Lowest per TBSeagate Expansion Desktop 20TB, External Hard Drive, USB 3.0, Data Rescue Services (STKP20000400)
Seagate·20TB
£359.99
£18.00/TB per TB
Compare external hard drives — portable 2.5" and desktop 3.5" models — from WD, Seagate, Toshiba, and more. Find the cheapest USB backup drives by price per terabyte in the UK.
From pocket-sized portable drives to powered desktop units for Time Machine and media libraries, we update Amazon UK prices daily. Filter by brand and capacity, then sort by £/TB to compare Expansion, Elements, and other popular ranges without guesswork.
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Lowest priceEzekers 500GB USB 3.0 USB C External Hard Drive – Ultra Fast & Slim Portable HDD Storage for PC, MacBook, Laptop, Xbox One and PS4, Black
ezekers·500GB
£20.24
£40.48/TB per TB
Most popularSeagate Portable Drive 5TB, External Hard Drive, Dark Grey, for PC Laptop and Mac, Data Rescue Services, Amazon Exclusive (STGX5000400)
Seagate·5TB
£136.76
£27.35/TB per TB
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Frequently asked questions
What is a good price per TB for an external hard drive?
In 2026, a good price per terabyte for an external hard drive is around £15-25/TB. High-capacity desktop drives (8TB+) can drop to £12-18/TB, while portable 2.5-inch drives typically cost £20-30/TB due to their compact size.
How much does an external hard drive cost?
External hard drive prices start from around £30 for a 1TB portable drive and range up to £300+ for high-capacity 20TB+ desktop models. The best value is typically in the 4TB-8TB range. We track prices daily from Amazon UK — check our comparison table for the latest deals.
Should I buy a portable (2.5") or desktop (3.5") external drive?
Portable 2.5-inch drives are powered via USB, making them truly portable. Desktop 3.5-inch drives require a power outlet but offer larger capacities and better value per TB. Choose portable for travel and convenience, or desktop for stationary backup and storage.
What USB connection do I need for external hard drives?
USB 3.0 (also called USB 3.2 Gen 1) offers speeds up to 5Gbps, which is plenty for hard drives. USB 3.2 Gen 2 (10Gbps) and USB-C are also common but won't make HDDs faster—they're limited by the drive's mechanical speed of around 150-200MB/s.
Can I use an external hard drive for PS4/PS5 or Xbox?
Yes, external USB drives work with gaming consoles for storing games. PS4 and Xbox support external HDDs for playing games directly. PS5 can use external HDDs for PS4 games and cold storage of PS5 games (which must be transferred to internal storage to play).
What is the cheapest external hard drive per terabyte?
The cheapest external hard drives per terabyte are typically high-capacity desktop models (8TB+) from Seagate and Western Digital. Portable drives offer slightly higher prices per TB but much more convenience. Check our table above sorted by price per TB for the current best deals.
Should I buy an external hard drive or external SSD?
External hard drives offer the best value per terabyte and higher maximum capacities. External SSDs are significantly faster (5-10x), more compact, and more durable but cost 2-4x more per terabyte. Choose an HDD for bulk backup storage, or an SSD if you need fast transfer speeds and portability.