Best External Drives for Backup - Live Prices

3-2-1, and why one drive is not a backup

The framing worth knowing is old, unglamorous and correct: three copies of anything you care about, on two different kinds of media, with one copy off-site. It predates the cloud and it survives every change in storage technology because it describes failure modes rather than products.

Measured against it, the standard arrangement — one external drive plugged permanently into the machine it backs up — is a second copy on second media with nothing off-site. That is a real improvement over nothing, and it protects against the single most likely event, which is the machine's own drive failing. It is worth doing.

What it does not protect against is everything that takes both at once, and that list is longer than people expect: theft of the machine and everything attached to it, fire, a power event that damages connected hardware, a spilled drink across a desk, and ransomware, which walks every mounted volume by design. In each of those, the permanently-connected backup drive is destroyed or encrypted alongside the original.

The fix is not expensive and does not require a cloud subscription. It is a second drive that is not in the building, swapped with the first on a schedule. That is the whole intervention, and it converts the arrangement from two copies in one place into a genuine off-site copy.

The rotation, in practice

Two drives. One connected and receiving backups; the other somewhere else entirely — an office, a relative's house, a locked drawer at a different address, a car if nothing better is available. On a schedule you will actually keep, you swap them: bring the off-site drive home, let it catch up, take the other one away.

Monthly is the interval most people can sustain, and sustainability is the whole game. A weekly rotation that lapses after six weeks protects less than a monthly one that runs for years. Pick the interval you will genuinely honour and set a recurring reminder, because the failure mode of this system is not technical, it is forgetting.

What the interval controls is your worst case. With monthly rotation, a fire takes at most a month of changes. Whether that is acceptable depends entirely on what the data is — for a household's photographs it usually is, and for a business it usually is not, which is where a cloud sync for the actively-changing subset earns its keep alongside the drives.

Two drives also gives you something the single-drive arrangement does not: a backup that survives the backup failing. Backup drives fail like any other drive, and they tend to fail unnoticed because nobody looks at them. With one drive, discovering that at the moment you need it is the worst possible time. With two, it is an inconvenience.

At desktop external prices, the second drive is the cheapest meaningful improvement available to most people's storage arrangements. The tables above show what it costs today.

Sizing against your data rather than your disk

The commonest sizing mistake is measuring against the wrong number. A 2TB laptop with 400GB actually used needs a backup target sized against the 400GB, and buying against the 2TB is buying five times more than the job requires.

Check the used figure first — About This Mac on macOS, or the drive properties on Windows — and size against that. Then apply the multiplier, because versioned backup systems store your data plus as much history as they can fit.

The standard guidance of at least twice the source data exists for a specific reason. At 1:1, a versioned system fills almost immediately and then spends its life deleting the history that makes it worth having. At 2:1 or better you keep months of versions, which is what lets you recover the file you broke three weeks ago rather than only the disk that died this morning. Recovering from your own mistakes is the more common need of the two.

Data also grows, and backup targets are bought infrequently, so leave headroom for the years the drive will be in service rather than for today. Buying a rung up is usually cheaper per terabyte anyway, which the tables above show directly.

One thing not to do is size the second drive differently from the first. Rotation only works if either drive can hold the full backup, and a smaller off-site drive turns into a partial backup that nobody notices is partial until it matters.

Which family, and why the cheapest is usually right

For backup specifically, the family decision is easier than for any other use on this site, and the answer is usually the cheapest one.

A desktop external hard drive is the correct default. It is the cheapest storage per terabyte you can plug straight into a machine, it reaches the largest capacities in this cluster, and a backup target sits on a desk next to a socket where the mains adapter is irrelevant. The money saved against the other families buys the second drive that makes the whole arrangement work.

A portable hard drive earns its place as the off-site half of a rotation, because that drive travels regularly and a bus-powered unit is simply easier to move. Pairing a desktop drive at home with a portable one that goes back and forth is a common and sensible arrangement.

A portable SSD is hard to justify as a backup target and easy to justify as something else. Backup is a bulk, sequential, unattended job — the properties an SSD is bought for do not apply, and you would be paying several times the rate per terabyte for benefits the workload does not use. The exception is somebody who needs a backup that also travels constantly, where the drive is doing two jobs.

The used market deserves a mention, and a careful one. A used external as the connected primary backup is a poor idea, because that drive is doing the important work. A used external as the off-site second copy in a rotation is defensible: it is a third copy of data that already exists in two places, and if it fails the arrangement degrades rather than breaks. Our deals page tracks used and new as separate price series so you can see which is genuinely cheap.

Testing the backup, which almost nobody does

A backup you have never restored from is a hypothesis. It is a reasonable hypothesis and it is usually correct, and the moment you find out is the moment it matters most.

The test does not need to be elaborate. Once a year, restore something real — not a test file you just created, but an actual document from a few months ago — and open it. That exercises the whole chain: the drive spins up, the backup software finds the version, the file comes back, and it is not corrupt. Ten minutes, once a year.

The failure this catches most often is not a dead drive. It is a backup that silently stopped running weeks or months ago because a drive letter changed, a password expired, an update reset a setting, or the target filled. Backup software is generally poor at making that loud, and people are generally good at dismissing notifications.

The second thing worth checking is what is actually included. Default backup configurations frequently exclude things people assume are covered — external drives themselves, network locations, virtual machine files, some application data directories. Looking once at what the job actually covers is worth more than any amount of drive specification.

For the drives themselves, our drive health section covers reading SMART attributes and recognising a drive that is on its way out. A backup drive that is failing quietly is worth catching while the other copy still exists.

Frequently asked questions

Sources

Specification claims on this page were checked against the pages below on 4 August 2026. Where a widely-repeated figure did not survive that check, we report what the source says now and say so in the text rather than repeating the familiar number.

1. DatacenterDisk Research - Live external drive price and stock database (DatacenterDisk.com, Live)
   Used for: every price, $/TB figure, stock state, condition badge, family classification and price-history range on these pages, plus the external-versus-bare-drive comparison and the shuck arithmetic, all computed from our own tracking of Amazon US listings
2. Western Digital - WD Elements, My Book and My Passport product pages (WesternDigital.com, 2026)
   Used for: series positioning and USB interface designations. These pages do NOT state which bare drive is inside any enclosure, which is why our recording-technology column reads 'not sourced' rather than naming one. Warranty terms did not resolve through our fetch path, so that column is a dash
3. Seagate Technology - Seagate Expansion and One Touch product pages (Seagate.com, 2026)
   Used for: series positioning and USB interface designations. As with WD, we found no Seagate document naming the drive inside an external enclosure. Warranty terms did not resolve through our fetch path
4. Samsung Electronics - Portable SSD T7 Shield product page (Samsung.com, 2026)
   Used for: USB 3.2 Gen 2 interface designation for the T7 Shield line, quoted as the maker's own specification string and not interpreted into a speed claim
5. DatacenterDisk Research - Shucking external drives — what the community finds inside (DatacenterDisk.com, 2026)
   Used for: teardown findings, carried as community reports that vary by production batch rather than as manufacturer specifications; the 3.3V power-disable pin issue
6. DatacenterDisk Research - Where to buy storage safely (DatacenterDisk.com, 2026)
   Used for: channel risk assessment behind the counterfeit and fake-capacity guidance on these pages
7. Sony Interactive Entertainment - USB extended storage on PS5 consoles (PlayStation.com, 2026)
   Used for: the platform rule that PS5 games cannot be played from USB extended storage and must be copied back to console storage to play, while PS4 games can be installed to and played directly from USB extended storage
8. Microsoft - Xbox Series X|S FAQ and Storage Expansion Card support (Xbox.com, 2026)
   Used for: the platform rule that a USB 3.1 external drive plays backward-compatible Xbox One, Xbox 360 and original Xbox titles directly, while titles optimized for Xbox Series X|S run from the internal SSD or the Storage Expansion Card