To back up your data, you need copies of your important files in more than one place. Nearly every device you own already includes a free backup tool. Your phone can copy itself to the cloud overnight, Windows and macOS both ship with backup software, and an inexpensive external drive covers the rest.
The goal is simple. If your laptop dies, your phone ends up in a lake, or ransomware locks every file you own, you should be able to restore your files and get on with your day. That takes about an hour of setup and almost no ongoing effort.
This guide covers the 3-2-1 rule that professionals use, the exact settings to turn on for iPhone, Android, Windows, and Mac, and how to make sure your backups will actually work when you need them.
The 3-2-1 Rule: One Habit That Covers Every Disaster
Security professionals recommend the 3-2-1 rule because it protects against every common way people lose files, all at the same time:
- 3 copies of your data: the original plus two backups.
- 2 different types of storage: for example, your computer's internal drive plus an external drive, or a drive plus a cloud service.
- 1 copy kept somewhere else: away from your home, so no single event can destroy everything at once.
Consider what this defends against. A failed hard drive takes out one copy, and you still have two. A burglar who takes your laptop and the drive next to it cannot touch the copy stored elsewhere. A house fire can ruin everything in one building, but not the offsite copy. And ransomware that encrypts every drive connected to your computer cannot reach a backup that is offline or sitting in a cloud account with version history. Device failure, theft, fire, and ransomware: one rule covers all four.
It sounds like a lot, but most of it can be automated in a single evening.
Start With the Cloud Storage You Already Have
The easiest offsite copy is a cloud service, and you almost certainly have one already. iCloud comes with every Apple device, OneDrive is built into Windows, and Dropbox works on just about anything. Your phone also ships with its own cloud backup.
These services all work the same way. You sign in once, choose which folders to protect, and they sync automatically in the background from then on. Your files stay reachable from any device, so a photo taken on your phone shows up on your laptop, and a document saved at your desk is available from a browser anywhere.
Free tiers are small, usually enough for documents but not for a full photo library. Paid plans big enough for a lifetime of photos cost a few dollars a month, which is cheap insurance for files you could never recreate.
One honest caveat: syncing is not quite the same as backup. Delete a file on one device and the deletion syncs everywhere too. Most services keep deleted files and older versions for around a month, which is what saves you from ransomware and from your own mistakes, so leave that feature on and empty the cloud trash carefully.
Back Up Your Phone in Five Minutes
Your phone probably holds your most irreplaceable files: photos and videos of the people you love. It is also the device most likely to be dropped, soaked, or stolen, so start here.
iPhone
iPhone backs up to iCloud automatically once the feature is on. Open Settings, tap your name at the top, then iCloud, then iCloud Backup, and switch it on. From that point the phone backs itself up whenever it is locked, charging, and on Wi-Fi, which usually means every night on the nightstand.
Android
Android phones have cloud backup built into settings as well. Open Settings and search for Backup, or look under System or Accounts and Backup, since the menu name varies by manufacturer. Turn it on and the phone will regularly save your contacts, messages, call history, app data, device settings, and photos to your account's cloud storage while it charges on Wi-Fi.
On either platform, confirm that photos and videos are included. They are sometimes controlled by a separate photos setting with its own switch.
Back Up Your Computer With Built-In Tools
Windows
Windows includes File History, which quietly copies your personal folders, such as Documents, Desktop, and Pictures, to an external drive and keeps older versions of every file. Plug in a drive, type File History into the Start menu search, and turn it on. It also lets you rewind a file to how it looked last week.
Windows also has Backup and Restore, an older tool that lives in Control Panel. Unlike File History, it can create a full system image: a complete snapshot of Windows, your programs, and your settings. If your drive fails outright, a system image lets you restore the whole machine instead of reinstalling everything from scratch. File History for your files plus an occasional system image is a strong combination.
Mac
macOS has Time Machine. Open System Settings, go to General, then Time Machine, and add an external drive as the backup disk. Time Machine keeps hourly backups for the past day, daily backups for the past month, and weekly backups beyond that, deleting the oldest as the drive fills. Once it is on, you can forget it exists until the day it rescues you.
External Drives: Your Local Copy, and Maybe Your Offsite One Too
An external hard drive or SSD is the natural second type of storage in the 3-2-1 rule. It is a one-time purchase, restores are fast because nothing has to download, and a drive with room for a typical household costs less than a tank of gas.
Two habits make an external drive far safer. First, disconnect it between backups. Ransomware encrypts every drive it can see, so a backup drive that is unplugged most of the time is out of its reach. Second, keep a simple routine, such as plugging it in on the first weekend of each month while you have your coffee.
Here is the part many guides miss: you do not need the cloud to satisfy the offsite copy. An external drive kept somewhere other than your home counts. A drawer at your office, a shelf at a relative's house, or a safe deposit box all work. The classic approach is to buy two identical drives, keep one at home and one offsite, and swap them every month or two. If cloud storage makes you uneasy or your internet connection is slow, this is a perfectly sound way to follow the rule.
Protect the Backups Themselves
Your backup account now holds a copy of your digital life, so lock the door. Protect it with a long, unique password, and let our password generator create one. Then turn on two-factor authentication so a stolen password alone cannot be used to log in and delete or download your backups.
Also check whether the email address attached to your backup account has appeared in a known data breach with our email breach checker. If it has, change that password first.
For external drives, turn on encryption so a lost or stolen drive is unreadable. On a Mac, check the encrypt option when you set up a Time Machine disk. On Windows, BitLocker can encrypt an external drive on supported editions. Write the recovery key down and keep it somewhere safe, because an encrypted backup without its key is no backup at all.
Test Your Backups Before You Need Them
A backup you have never restored from is a hope, not a plan. Corrupted drives, full cloud accounts, and backups that silently stopped months ago are all common. A few times a year, spend ten minutes on a fire drill:
- Restore one file from File History or Time Machine and open it.
- Download a photo and a document from your cloud account and check that they open.
- On your phone, open the backup screen in Settings and confirm the last successful backup is recent.
- If you keep an offsite drive, plug it in, make sure it mounts, and refresh its contents.
If anything looks wrong, you found out on a calm Tuesday instead of the worst day of your year.
Where to Start Tonight
Protect the files no store can sell you again first: family photos and videos, tax and medical records, work and school projects, and personal notes. Programs and operating systems can always be reinstalled. Here is a plan you can start this evening:
- Tonight: turn on your phone's cloud backup and confirm photos are included. Five minutes, and it protects the files you would miss most.
- This week: sign in to iCloud, OneDrive, or Dropbox on your computer and put your documents folder inside the synced folder.
- This weekend: buy an external drive, then switch on File History or Time Machine and let the first backup run overnight.
- This month: secure your cloud account with a strong password and two-factor authentication, and consider a second drive to keep somewhere outside your home.
- Every few months: restore one file as a test and check your phone's last backup date.
Work down that list and you will have the full 3-2-1 setup: three copies, two kinds of storage, one offsite. From then on, the worst a dead laptop or a stolen phone can do is cost you an afternoon.
