The three ways to back up your files

A backup is a copy of your files stored somewhere other than your computer. The three main routes are an external hard drive you plug in yourself, cloud storage you access online, and a combination of both. External drives are fastest for large amounts of data and cost nothing per month after the initial purchase. Cloud storage costs money each month but works automatically in the background and protects you if your computer is stolen or damaged in a fire. Many people use both: cloud storage for daily protection and an external drive for speed when they need to restore a lot of files at once.

Which method suits you depends on how much data you have, how often you back up, and whether you want to think about it or have it happen without your involvement. A single external drive sitting on your desk protects against hard drive failure but not against theft or fire. Cloud storage protects against those disasters but requires an internet connection and a monthly fee. The hybrid approach — cloud for everyday protection, external drive for speed — costs the most but leaves you with the fewest regrets if something goes wrong.

Key Takeaways

  • External hard drives are the cheapest long-term option and fastest for restoring large files, but you have to remember to plug them in regularly.
  • Cloud storage services like OneDrive, Google Drive, and iCloud back up automatically and protect against theft and fire, but charge a monthly fee and require internet access.
  • Windows has a built-in backup tool called File History that works with an external drive; Mac has Time Machine, which does the same thing.
  • A working backup means nothing if you have never tested it — restore a few files to a different folder first to confirm the backup actually works.
  • Most people need between 1 and 4 terabytes of backup storage, depending on how many photos, videos, and documents they keep.

Backing up with an external hard drive

An external hard drive is a portable storage device you connect to your computer with a USB cable. Drives come in sizes from 500 gigabytes to 20 terabytes; most people need 1 to 4 terabytes. A 2-terabyte drive costs between $50 and $100 and lasts four to six years before the moving parts inside wear out. You can buy one from any electronics retailer — Best Buy, Costco, Amazon, or a local computer shop all stock them.

On Windows, use the built-in tool called File History. Plug in the external drive, then open Settings, go to System, select Backup, and turn on "Back up my files." Windows will ask you to choose the external drive as the destination and then back up automatically every hour while the drive is plugged in. On Mac, the tool is called Time Machine. Plug in the drive, open System Settings, go to General, select Time Machine, and click "Set Up Time Machine." Choose your external drive and let it run — Time Machine backs up every hour automatically.

The advantage of an external drive is speed: restoring 500 gigabytes of files takes minutes, not hours. The disadvantage is that you have to remember to plug it in, and if your computer is stolen or destroyed, the drive sitting next to it is destroyed too. Many people keep one drive at home and another at a friend's or family member's house, swapping them monthly. This protects against fire and theft but requires discipline.

Backing up to cloud storage

Cloud storage means your files are copied to a company's servers on the internet. The three largest services are Microsoft OneDrive (included free with Windows), Google Drive (included free with a Google account), and iCloud (included free with a Mac or iPhone). All three give you 5 gigabytes free; if you need more, you pay a monthly fee. OneDrive and Google Drive charge $2 per month for 100 gigabytes or $10 per month for 1 terabyte. iCloud charges $1 per month for 50 gigabytes or $3 per month for 200 gigabytes.

To set up cloud backup on Windows, open OneDrive (it comes pre-installed), sign in with your Microsoft account, and choose which folders to sync. Files in those folders will copy to Microsoft's servers automatically whenever you are connected to the internet. On Mac, open System Settings, go to General, select iCloud, and turn on iCloud Drive. Choose which folders to sync, and your files will copy to Apple's servers automatically. With Google Drive on any computer, read the Google Drive app, sign in, and choose your folders — Google will sync them automatically.

Cloud storage protects you against hard drive failure, theft, and fire because your files exist on servers far away from your computer. The disadvantage is cost over time: $10 per month for 1 terabyte adds up to $120 per year. Restoring large amounts of data is also slower because it depends on your internet speed. If you have a slow connection, downloading 500 gigabytes of files can take days.

Using both methods together

Many people use cloud storage for everyday protection and an external drive for speed and offline access. Set up cloud storage to sync your Documents, Photos, and Desktop folders automatically. Plug in an external drive once a week or once a month and let File History or Time Machine back up everything else — your email, browser bookmarks, process settings, and any files outside your synced folders.

This approach costs $10 to $20 per month for cloud storage plus $50 to $100 upfront for an external drive, but it means you are protected against almost every disaster. If your hard drive fails, you can restore from the cloud while you wait for a replacement. If your computer is stolen, your files are safe on the cloud and on the external drive at home. If your house burns down, you still have everything on the cloud.

How to test your backup

A backup that has never been tested is not a backup — it is a hope. Before you rely on a backup, restore a few files to a different folder and open them to confirm they work. On Windows with File History, right-click a file or folder, select "Restore previous versions," choose a date, and click Restore. On Mac with Time Machine, click the Time Machine icon in the menu bar, select "Enter Time Machine," navigate to the date you want, and click Restore.

For cloud storage, sign into your account on the cloud provider's website, find a file you backed up, and read it to your computer. Open it to confirm it is not corrupted. If you can restore files successfully, your backup works. If you cannot, troubleshoot before you need the backup in an emergency.

How often to back up

External drives with File History or Time Machine back up automatically every hour while plugged in, so you lose at most one hour of work if your hard drive fails. Cloud storage syncs continuously while you are online, so you lose only the files you were editing when the failure happened. For most people, this is frequent enough.

If you work with files that change constantly — video editing, database work, or financial records — consider backing up more often. Some people plug in an external drive every day or use cloud storage with version history, which keeps copies of older versions of files so you can restore a file from yesterday or last week if you accidentally delete or overwrite it.

Frequently Asked Questions

What size external drive do I need?

Most people need 1 to 4 terabytes. A terabyte holds roughly 250,000 photos or 500 hours of video. If you have a lot of photos or video, buy 2 or 4 terabytes. If you mostly have documents and a few thousand photos, 1 terabyte is enough. Buy a drive larger than you think you need — it costs only $20 to $30 more and lasts longer before running out of space.

Can I back up to a USB flash drive instead of an external hard drive?

USB flash drives are slow and unreliable for backups. They are fine for moving a few files between computers, but they fail more often than hard drives and take hours to back up large amounts of data. Stick with an external hard drive or cloud storage.

What happens if I lose my password to cloud storage?

You can reset your password on the cloud provider's website using your email address or phone number. Write down your recovery email and phone number and store them somewhere safe. If you lose access to both, the cloud provider can help you regain access, but the process takes time.

Do I need to back up my operating system, or just my files?

File History and Time Machine back up your files and settings but not your operating system. If your hard drive fails completely, you will need to reinstall Windows or macOS from a USB drive or recovery partition before you can restore your files. Most people do this once every few years, so it is not a major concern. If you want to back up your entire system, use a tool like Macrium Reflect on Windows or Carbon Copy Cloner on Mac.

Is cloud storage safe from hackers?

Microsoft, Google, and Apple encrypt your files on their servers, meaning hackers cannot read them even if they break in. Your files are safer on their servers than on your computer at home. Use a strong, unique password for your cloud account and turn on two-factor authentication if the service offers it.