The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →There is no one backup-drive size that suits everyone. Measure the data your backup will actually include, allow room for older versions and future growth, then choose a compatible destination. For a Mac using Time Machine, Apple recommends a disk with at least twice the Mac’s storage capacity. For phones and cloud backups, use the backup estimate and the account’s remaining quota—not the device’s advertised capacity.
How to size backup storage
- Decide what must be recoverable. List the computers, phone data, photos and videos, work files, and other material you need to restore. Check what the selected backup method includes: syncing a folder is not automatically a complete device backup.
- Measure the actual backup. Use the backup app’s estimate when available. On a computer, check the selected tool’s included folders and their current size. For cloud services, account for other content sharing the same quota.
- Choose how much history to keep. A drive that fits only one current copy may not leave room for earlier versions. Time Machine keeps prior backups and deletes the oldest as its disk fills.
- Allow for growth and shared use. Leave capacity for data added over time and for any other files or services using the same storage. There is no supported universal multiplier for Windows or generic cloud backups.
- Check compatibility before buying. Confirm the connection, supported file system, and backup-software requirements. Apple advises using the Time Machine disk only for backups.
Apple devices: iCloud and Time Machine
Check an iPhone or iPad’s next iCloud backup
Apple recommends checking the device’s estimated backup rather than guessing from its storage capacity. Open Settings > [your name] > iCloud > iCloud Backup, select the device if needed, and look for Next Backup Size. The estimate may take a few minutes to appear. If it exceeds available iCloud space, Apple suggests reducing the data included in the backup or upgrading storage. You can also turn off backup for selected apps or remove an old device backup. Take care: deleting the backup for the device you are currently using also turns off iCloud Backup for that device. Apple’s iCloud backup instructions explain these controls.
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Size a Time Machine disk
For a Mac, Apple’s specific guidance is to use a disk with at least twice the Mac’s storage capacity. Its example is a 1 TB Mac with a 2 TB-or-larger backup disk. This is Apple’s recommendation for Time Machine, not a general rule for every backup program. Time Machine retains earlier backups and removes the oldest when the disk runs out of space, so a larger disk can preserve more history. See Apple’s Time Machine setup guidance.
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Time Machine can use directly connected external storage, another Mac configured as a shared destination, or a network-attached storage device that supports Time Machine over SMB. Apple says AFP-based Time Machine backup is not recommended and is unsupported in macOS 27 or later. NAS compatibility can depend on software and OS versions, so confirm the manufacturer’s current instructions before purchase. Apple lists supported Time Machine destinations.
#1 Best Overall
- Easily store and access 2TB to content on the go with the Seagate Portable Drive, a USB external hard drive
- Designed to work with Windows or Mac computers, this external hard drive makes backup a snap just drag and drop
- To get set up, connect the portable hard drive to a computer for automatic recognition no software required
- This USB drive provides plug and play simplicity with the included 18 inch USB 3.0 cable
- The available storage capacity may vary.
Google Account and Android storage
A standard Google Account includes up to 15 GB shared across Drive, Gmail, and Photos; it is not necessarily 15 GB free for device backups. Check remaining account storage before relying on it. When the account reaches its limit, new Google Photos backups stop. Google explains the shared quota in its Google Account storage help and describes Android backup.
Google Photos’ Original quality keeps captured resolution and counts toward quota. Storage saver also counts for newer uploads; it may resize photos above 16 MP to 16 MP and video above 1080p to 1080p, with exceptions. Some files may not be compressed, so this is a quality-versus-space choice, not a predictable compression ratio. Details are in Google Photos’ quality settings guide.
Rank #2
- Easily store and access 5TB of content on the go with the Seagate portable drive, a USB external hard Drive
- Designed to work with Windows or Mac computers, this external hard drive makes backup a snap just drag and drop
- To get set up, connect the portable hard drive to a computer for automatic recognition software required
- This USB drive provides plug and play simplicity with the included 18 inch USB 3.0 cable
- The available storage capacity may vary.
Windows: local drive or cloud
Microsoft’s guidance frames this as a choice based on access and transfer constraints. Cloud backup can make files convenient to reach across devices without buying a drive. An external or network drive can make more sense when internet access is unavailable or uploading a large collection would take too long or cost too much. Windows File History can automatically save versions of libraries to an external drive or network location. See Microsoft’s File History instructions and its Windows backup options.
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The File History instructions cover Windows 10 and Windows 11. Windows 10 support ended on October 14, 2025; do not assume it continues to receive free security updates.
Rank #3
- Easily store and access 1TB to content on the go with the Seagate Portable Drive, a USB external hard drive.Specific uses: Personal
- Designed to work with Windows or Mac computers, this external hard drive makes backup a snap just drag and drop. Reformatting may be required for Mac
- To get set up, connect the portable hard drive to a computer for automatic recognition no software required
- This USB drive provides plug and play simplicity with the included 18 inch USB 3.0 cable
- The available storage capacity may vary.
What should you buy?
| Option | Best suited to | Trade-offs |
|---|---|---|
| External hard drive or SSD | Local backup, large data sets, or limited internet | Must be connected or otherwise available for scheduled backups; check port and software support. Physical loss or damage can affect the backup. |
| Network drive or NAS | A shared destination or multiple computers, if the backup software supports it | Network setup and compatibility matter. A NAS in the same home or office is not an off-site copy. |
| Cloud storage or backup | Off-site storage and convenient access across devices | Requires internet; quota may be shared with other content. Price and availability vary by country and date. |
| Local plus off-site backup | People who want convenient local restores and another copy elsewhere | Requires more setup and may cost more, but protects against some risks a single local copy cannot. |
For a straightforward local computer backup, an external hard drive is a practical category to consider. Choose capacity from your measured backup size and retention plan, then verify the port and software compatibility. An external SSD is another physical option, but no speed or durability comparison is established here. For a networked household, consider a compatible NAS only if you are comfortable with the setup and network requirements.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Make the backup resilient, not just large
A single drive can be lost, damaged, stolen, or affected by ransomware along with the computer it backs up. CISA’s 3-2-1 rule is to keep three copies of important data (the primary copy and two backups), use two types of media, and keep one copy off-site. For a household, that might mean working files, a local backup drive, and a separate cloud or off-site copy. Keep sensitive data encrypted and media physically secure where appropriate. The rule is a useful framework, not a guarantee against every failure. See CISA’s Data Backup Options.
Quick Recap
Best Value
- [Upgraded Version] - This external hard drive features a mirrored logo stripe combined with a striped anti-slip design, and the rounded corners of the casing make it easier to grip. The stripes also have a heat dissipation function, ensuring stable and fast data transfer.
- 【Ultra-thin and quiet】 - The motherboard adopts JMicron 578 noise-free solution, giving you a quiet working environment. Lightweight and portable size designed to fit in your pocket for easy portability.
- 【Ultra-Fast Data Transfers】 - Pairing this external hard drive with JMicron 578 solution USB 3.0 and USB 2.0 interfaces enables blazing-fast data transfer. It boasts theoretical read speeds of up to 125MB/s and write speeds of up to 103MB/s.
- 【Plug and Play】 - With no software to install, just plug it in and the drive is ready to use.The hard disk chip is wrapped with an aluminum anti-interference layer to increase heat dissipation and protect data.
- 【What You Get】 - 1 x Portable Hard Drive, 1 x USB 3.0 Cable, 1 x User Manual, Gift-type shell packaging ,Three-year manufacturer's warranty and free technical support services.
Rank #4
- Easily store and access 4TB of content on the go with the Seagate Portable Drive, a USB external hard drive.Specific uses: Personal
- Designed to work with Windows or Mac computers, this external hard drive makes backup a snap just drag and drop
- To get set up, connect the portable hard drive to a computer for automatic recognition no software required
- This USB drive provides plug and play simplicity with the included 18 inch USB 3.0 cable
- The available storage capacity may vary.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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