You reach for your phone on the train and it is gone, or your laptop shows a black screen on the morning a form is due. The device can be replaced; the photos and documents on it often cannot, unless a copy lives somewhere else. This WhatsOnTech guide shows you how to back up your files on your phone and computer with tools you probably already have, and how to check that the copies work.

Why your files need a backup

A backup is a separate copy of your files that you can bring back if the original disappears. The reasons are usually ordinary:

  • Lost, stolen or broken devices. A dropped phone or a bag left on a bus takes your files with it.
  • Accidental deletion. Clearing space can remove the wrong thing, and you may not notice for weeks.
  • Ransomware. This harmful software locks your files and demands payment to unlock them. It often arrives through a scam email or fake download, one more reason to learn how to spot a scam.

With a recent backup, each of these becomes an annoying afternoon rather than a permanent loss.

Sync is not quite a backup

If your files appear on every device, that is usually sync, which keeps the same files matching everywhere. It is convenient, but it copies mistakes too: delete a photo on your phone and sync can remove it everywhere.

Most sync services keep deleted files in a recycle bin for a limited time, which helps. A true backup keeps earlier copies that your everyday changes do not touch. The WhatsOnTech rule of thumb: enjoy sync, but never treat it as your only safety net.

The 3-2-1 idea, made simple

A widely used rule called 3-2-1 means not keeping all your eggs in one basket:

  1. Three copies. Your original files plus two backups.
  2. Two different kinds of storage. For example, cloud storage (files kept on a company’s computers over the internet) plus an external drive.
  3. One copy away from home. A cloud backup counts, and it survives a fire or burglary.

Each option has a trade-off. Cloud backups run by themselves and live off-site, but beyond the free allowance you usually pay a monthly fee, and your files sit on someone else’s servers. Our plain guide to tech jargon explains the end-to-end encryption that keeps some backups readable only by you.

A drive at home is a one-off cost, fast and private, but it can be lost along with the house. Ransomware can also reach a drive left plugged in, which is why the UK’s National Cyber Security Centre advises disconnecting backup drives when you are not using them.

Anyone who gets into your cloud account can reach your backups too. The WhatsOnTech advice is to protect that account with a strong password and two-factor sign-in.

How to back up your files on your phone

Phones are the easiest place to start, because both major systems have backup built in.

iPhone

Open Settings, tap your name, then iCloud, then iCloud Backup, and turn on Back Up This iPhone. It then backs up automatically when it is plugged in, locked and on Wi-Fi. If you use iCloud Photos, your photos are synced rather than stored in the backup, so the sync caution applies.

You can also back up to a Mac or Windows PC with a cable, and Apple’s guide to backup methods compares the two. Doing both is a tidy step towards 3-2-1.

Android

Open Settings, tap Google (or Google services), then All services, then Backup. Menus vary by maker; if yours differs, search Settings for Backup. It saves app data, contacts, call history, settings and text messages to your Google account, and Google Photos has its own backup setting for pictures and videos.

Backing up a Mac or Windows computer

The WhatsOnTech approach for computers is two layers: an external drive for full, fast copies, and cloud storage for the off-site one.

  • Time Machine on a Mac. Plug in a drive, open System Settings, then General, then Time Machine, and choose Add Backup Disk. It backs up every hour while the drive is connected, and Apple suggests a drive at least twice the size of your Mac’s storage.
  • File History on Windows 11. Connect a drive, open Control Panel, choose System and Security, then File History, and turn it on. Microsoft’s File History instructions show how to bring back an older version.
  • Windows Backup and OneDrive. Search the Start menu for Windows Backup to send folders such as Documents and Pictures to OneDrive, Microsoft’s cloud storage. It works by syncing, so pair it with File History.

Leaving the drive connected keeps copies freshest but also exposed, so plugging it in once a week is a sensible middle ground. A backup also makes bigger jobs less nerve-racking, such as speeding up a slow laptop.

Make it automatic, then test it

The most important part of how to back up your files is making it happen without you. Switch on the automatic options, then set a calendar reminder for anything manual, such as plugging in a drive. Weekly suits most people, or more often if you create a lot of work.

Then test it, because a backup you have never restored is only a hope. Restore one unimportant file to a different folder and open it, and check that recent phone photos appear in your cloud library on another device. WhatsOnTech suggests this starter checklist:

  1. Turn on phone backup today. Include your photos.
  2. Get one external drive. Set up Time Machine or File History and let the first backup finish.
  3. Add an off-site copy. Put irreplaceable folders, especially family photos, in cloud storage.
  4. Lock down the accounts. Add two-factor sign-in to your cloud account.
  5. Test a restore every few months. Bring back one file and check it opens.

The takeaway

Learning how to back up your files is mostly about setting things up once and checking now and then: built-in backups on, one copy on a drive, one away from home, and proof you can bring files back. The trade-offs are modest, a little money for storage and a little thought about privacy. Turning a frightening what-if into a quiet routine is what WhatsOnTech sets out to do across all our software guides.