The fastest way to back up your computer depends on what you own and how much data you have

A backup is a copy of your files stored somewhere other than your computer — usually an external drive, a cloud service, or both. If your hard drive fails, you get stolen, or your system crashes, a backup lets you recover your photos, documents, and settings instead of losing them permanently. Most people need two things: a full system backup (everything on your computer) and a way to back up new files automatically so you do not have to remember to do it manually.

The method you choose depends on whether you use Windows, macOS, or Linux, how much storage space you need, and whether you want backups stored at home or online. This guide covers the real tools built into each operating system, plus external options that work across all of them.

Key Takeaways

  • Windows includes File History (for files) and System Image (for everything), both built in and free; macOS includes Time Machine, which backs up to an external drive automatically.
  • External hard drives are the fastest and cheapest way to store large backups at home, but they can fail or be lost, so a second backup elsewhere is wise.
  • Cloud services like OneDrive, Google Drive, and iCloud back up files automatically and keep them safe offsite, but uploading large amounts of data takes time and may cost money for extra storage.
  • The safest approach is a combination: a local external drive for speed and a cloud service for protection against theft or disaster.
  • Set up automatic backups once, then they run in the background without you having to think about them.

Windows: File History and System Image

Windows 10 and Windows 11 come with two built-in backup tools. File History backs up your Documents, Pictures, Music, Videos, and Desktop folders automatically to an external drive or network location. System Image creates a complete snapshot of your entire system, including Windows itself, all your programs, and all your files — useful if your computer stops working and you need to restore everything.

To set up File History on Windows 10 or 11, plug in an external drive, then go to Settings > System > Storage > Advanced Storage Options > Backup Options. Click "Add a drive" and select your external drive. Turn on "Automatically back up my files" and choose how often (daily, hourly, or when you plug in the drive). Windows will then copy your files to that drive on the schedule you set. You can restore individual files by opening File History and browsing to the version you want.

To create a System Image, go to Settings > System > About > Advanced System Settings > System Protection > Create a restore point. Click "Create" and follow the prompts. This creates a complete copy of your system that you can use to restore your computer if it fails. Keep this image on an external drive separate from your main backup, so you have it if your primary drive dies.

macOS: Time Machine

macOS includes Time Machine, which automatically backs up your entire system to an external drive. Plug in an external drive (at least 2 terabytes if you have a lot of files), and macOS will ask if you want to use it for Time Machine. Click "Use as Backup Disk" and Time Machine starts when ready. It backs up every hour by default and keeps hourly backups for 24 hours, daily backups for a month, and weekly backups for all previous months.

To restore files, open Time Machine from the Applications folder or click the Time Machine icon in the menu bar. Browse to the date you want, select the files you need, and click Restore. If your Mac stops working entirely, you can restore the whole system from a Time Machine backup during startup by holding Command-R and choosing Restore from Time Machine Backup.

Time Machine works best when the external drive stays connected. If you unplug it, backups pause until you plug it back in. For offsite protection, use Time Machine alongside a cloud service like iCloud or Backblaze.

Linux: Built-in tools and third-party options

Linux distributions vary, but most include backup tools in their system settings. Ubuntu, for example, includes Deja Dup (also called Backups), which backs up to an external drive or cloud service. Open Settings > Backups, select where to store backups, choose which folders to include, and set a schedule. Deja Dup encrypts backups and can restore individual files or your entire system.

Other Linux distributions may use different tools — check your system's Settings or Help menu for "Backup" to find what is available. If your distribution does not include a graphical backup tool, command-line tools like rsync and tar can copy files to an external drive, though they require typing commands rather than clicking buttons.

External hard drives: Speed and simplicity

An external hard drive is the fastest and cheapest way to store a full backup. A 2-terabyte external drive costs between $50 and $100 and holds backups for most home computers. Plug it in, set up automatic backups (as described above for your operating system), and it runs in the background. Restoring files is also fast because the drive connects directly to your computer via USB.

The downside is that external drives can fail, get lost, or be stolen along with your computer. For that reason, keep your external drive in a different location from your computer — at a friend's house, a safe deposit box, or a desk drawer in another room. If you have only one external drive and it fails, you lose both your computer and your backup.

External drives last 3 to 5 years on average. If yours is older than that, consider replacing it or adding a second one. Check your backups occasionally by restoring a test file to make sure the backup actually works.

Cloud services: Automatic and offsite

OneDrive (Windows), Google DriveiCloud (macOS and iOS) automatically sync files to the cloud as you save them. This protects against local drive failure and theft, and you can access your files from any device. The catch is that uploading large amounts of data takes time — a 500-gigabyte backup over a typical home internet connection can take days or weeks.

Most cloud services offer free storage (5 to 15 gigabytes) but charge for larger amounts. OneDrive costs $2 per month for 100 gigabytes, Google One costs $2 per month for 100 gigabytes, and iCloud costs $0.99 per month for 50 gigabytes. If you have more than a few gigabytes of files, the cost adds up. Backblaze and Carbonite are dedicated backup services that cost $7 to $10 per month for unlimited storage and back up your entire computer automatically.

Cloud services work best for documents, photos, and settings that change regularly. For a complete system backup, combine cloud storage with an external drive — the external drive handles the large initial backup, and the cloud service keeps new files safe.

Combining methods for the strongest protection

The safest approach uses both local and cloud backups. Set up an external drive for fast, complete backups of your entire system, and set up a cloud service to back up important files automatically. This way, if your external drive fails, your cloud backup has your recent files. If your computer is stolen, the external drive at another location is still safe. If your house burns down, your cloud backup survives.

Start with whichever method matches your situation: if you have an external drive already, set up File History or Time Machine today. If you do not have an external drive but have a cloud account, turn on automatic syncing for your Documents and Pictures folders. Then add the second method when you have time. A partial backup is better than no backup.

Test your backup by restoring a file you do not need — a photo, a document, something you can afford to lose. If the restore works, you know your backup is real. If it fails, you have found the problem before you actually need the backup.

Frequently Asked Questions

How often should I back up my computer?

Set up automatic backups and let them run on their own schedule. File History, Time Machine, and cloud services all back up continuously or on a daily schedule. Manual backups are straightforward to forget, so automatic is better. If you work with important files daily, weekly backups at minimum keep you from losing more than a week of work.

What size external drive do I need?

A drive should be at least as large as your computer's hard drive, and ideally larger so you can keep multiple backup versions. If your computer has a 500-gigabyte drive, get a 1-terabyte or 2-terabyte external drive. If you have a 1-terabyte drive, get a 2-terabyte or 4-terabyte external drive. Larger drives are cheap insurance.

Can I back up to a network drive instead of an external drive?

Yes. File History and Time Machine both support network drives (a shared drive on another computer or a network-attached storage device). Network backups are slower than external drives but let you back up without plugging anything in. Make sure the network drive is reliable and stays powered on.

What if my backup is taking too long?

The first backup is always the slowest because it copies everything. Plug in your external drive and let it run overnight. After that, backups are faster because they copy only new and changed files. If cloud backups are slow, start with just your Documents and Pictures folders, then add more later as bandwidth allows.

Do I need to encrypt my backups?

If your backup contains sensitive information (financial records, passwords, medical data), encryption protects it if the drive is lost or stolen. File History, Time Machine, and most cloud services support encryption. Turn it on when you set up the backup — it adds little overhead and protects your data.