The three categories of authentication factor Three columns showing something you know (a password or PIN), something you have (a phone, hardware key, or passkey), and something you are (a fingerprint or face). Two of the three are required to unlock the account. Text below explains that "two-factor" means two different categories, not two of the same. any two unlocks 1 Something you know • A password • A PIN • A recovery phrase • An answer to a security question Can be stolen, guessed, or reused 2 Something you have • Your phone (SMS, app, push) • A hardware security key • A passkey on your device • A code from an authenticator Requires possessing the device 3 Something you are • A fingerprint • Face recognitio...
How to Back Up Your Phone and Computer (Without Paying for Extra Storage)
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Original diagram — three copies of the same data, on two different media types, with one copy held off-site.
How to Back Up Your Phone and Computer (Without Paying for Extra Storage)
Most people who believe they back up their phone are actually just syncing it. These are different
things, and the difference matters at exactly the moment you need it to work.
This guide covers what backing up actually means, why "I use iCloud" or "I have Google Photos" is
not the same as a backup, and how to set up a real one using free tools and hardware you may already
own. It includes specific steps for both phones and computers, with honest notes about where the
free options have limits.
The framing throughout is the standard one used by people who do this professionally: the
3-2-1 rule. Three copies of important data, on two different types of media, with
one copy stored off-site. Everything below is an application of that rule to phones and computers
in a home context.
Key takeaways
Sync is not backup. If you delete a photo from your phone and it disappears from iCloud or Google Photos, that is sync — the deletion propagated. A backup would have preserved the deleted copy.
The 3-2-1 rule is the standard: three copies, two different media, one off-site.
You can usually achieve this without paying for extra cloud storage — an existing external drive and free cloud tiers cover most people.
The free methods have real limits. Honest about what those are, so you can decide what you actually need.
A backup you have never tested is not a backup. Restoring one file is the only test that counts.
1. Sync is not backup: the trap most people fall into
iCloud, Google Photos, OneDrive, Dropbox and the rest are usually described as backup services.
They are not, unless you specifically configure them that way. Their default behaviour is
synchronisation: the state of your files on their servers mirrors the state on your
devices. When you delete a photo from your phone, the deletion propagates to the cloud. When your
phone is stolen, the photos that were only on the phone and not yet synced are gone.
This is a feature, not a bug. Sync makes the same files available on every device, updates them when
they change, and keeps everything consistent. That is what most people actually want most of the
time. But it is not a backup, because a backup is defined by its ability to recover a state you can
no longer access through normal operations.
Original diagram — the difference is not the storage location. It is whether deletions and changes propagate.
There are exceptions worth knowing. Some cloud services do offer versioning and trash that preserve
deleted files for a limited period — Google Photos keeps deleted items in a trash bin for 60 days,
iCloud Photos keeps them for 30 days. Both are useful. Both are also time-limited, and both are
features of the sync service rather than a backup strategy.
The more serious problem is the phone-stolen-and-never-synced scenario. If your phone is stolen or
damaged before its photos have finished uploading to the cloud, those photos were never in the
cloud. Sync only protects what has already been uploaded. A backup that runs on a schedule from a
device you still control preserves more.
This distinction connects directly to the earlier guide on
what cloud computing actually is —
the cloud service is a copy on someone else's server, and the question of what that copy represents
depends entirely on how you set it up.
2. What to back up, and what you can skip
Not everything on your devices is worth protecting. Being selective keeps backup small enough to fit
within free tiers and manageable to maintain.
Original diagram — what is worth protecting, and what is genuinely fine to skip.
The photo category deserves emphasis because it is where most people's loss is concentrated. Photos
are usually the largest personal data category and the only one that genuinely cannot be recreated.
Documents can often be re-requested from the institution that issued them. Messages can sometimes be
recovered from a service. A photo from a specific moment cannot be recreated at all.
The password manager export deserves its own note. Even the best password manager can lock you out
if you forget your master password, and some vaults can become unrecoverable if the device holding
the only copy fails. Most managers offer an encrypted export file you can save to your backup media.
It is worth doing once and updating when you change the master password.
3. Backing up your phone without buying storage
What free storage you actually get
The honest limits, for the two main platforms:
Apple iCloud: 5 GB free. This is enough for contacts, calendar, notes, and app data, but not enough for photos or full device backup. Full device backup requires iCloud+, starting at 50 GB for a small monthly fee. The article's free-method approach sidesteps this by not relying on iCloud for photos.
Google One (Android): 15 GB free, shared across Gmail, Drive and Google Photos. This is enough for a moderate number of photos if you use "Storage saver" quality rather than original quality. It is not enough for years of photos at original quality.
Free method 1: Google Photos at reduced quality (both platforms)
Google Photos works on both iPhone and Android. Photos uploaded at "Storage saver" quality (which
Google describes as "reduced quality" — they compress slightly but remain visually fine for most
uses) count against the 15 GB free limit but use far less space than originals. This makes 15 GB go
much further than it would at original quality.
The setup: install Google Photos, sign in with a Google account, turn on "Back up and sync,"
and set upload size to "Storage saver." On iPhone, also allow access to your full photo library in
the app's permissions.
Two important caveats. First, this is sync, not backup, by the earlier definition — a
deletion on the phone will propagate. Second, Google Photos' trash preserves deleted items for 60
days, which is useful but time-limited. To make this a real backup, you need a second copy
elsewhere — which is what the next method provides.
Free method 2: computer-to-phone periodic import
The most genuinely free backup method is also the least fashionable: plug your phone into your
computer periodically and copy photos across via the file system. On iPhone, this uses the
Photos app (Windows) or Image Capture (Mac). On Android, the phone appears as a USB drive and you
can copy the DCIM folder directly.
This is a backup in the strict sense because the copy on your computer is independent of the phone.
If the phone is stolen, the photos are already on the computer. If you delete a photo on the phone,
the copy on the computer remains. It is not automatic, so you have to remember to do it — but it is
the most reliable no-cost option.
A reasonable cadence is monthly, plus before any major trip. Combined with the cloud sync above,
this gives you the two-copies-on-different-media part of the 3-2-1 rule. Adding an external drive
gives you the third copy.
Free method 3: use the "shared album" or "partner sharing" feature
Both Google Photos and iCloud Photos have a "shared album" or "partner sharing" feature that lets
you share photos with a specific person or account. Sharing with a second account you own — either
a family member's account or a second account you create — creates a second copy that is not
affected by deletions on the primary account.
This is an unusual use of the feature, but it works and it is free. The limitation is that shared
albums do not always preserve full metadata or original quality, and the person you share with
gains access to your photos. Reasonable if you are sharing with a partner or a trusted family
member; not a good idea with a stranger.
Free method 4: phone-to-phone or phone-to-tablet mirror
If you have an older phone or a tablet that is not your daily driver, it can serve as a second
physical location for backups. Most cloud services allow multiple devices to be signed in to the
same account; syncing an old phone that stays at home gives you a copy on that device's local
storage as well as whatever is in the cloud.
This works best if the secondary device has enough storage to hold a copy — which older phones
sometimes do not. But for a subset of important photos, it is a genuinely free option.
What not to rely on
Some common "backup" methods are not backups:
iCloud Photo Library alone. It is sync, not backup. If you delete a photo and it syncs, the deletion propagates. And if your phone is stolen before syncing, the un-synced photos are gone.
Google Photos alone. Same reasoning, plus the trash window is 60 days, not indefinite.
WhatsApp backup to iCloud or Google Drive. These are covered by the same limits — the backup is a snapshot, but it lives in the same cloud account as everything else. If you lose access to the Google or Apple account, you lose the backup too.
Emailing yourself photos. Works for a small number, but breaks down at scale, and email is not designed for this.
4. Backing up your computer without buying storage
Free method 1: File History on Windows
Windows includes File History — a built-in tool that copies your files to a separate drive on a
schedule. It requires an external drive (or a large USB stick), but no subscription.
Setup: plug in an external drive, open Settings → Update & Security → Backup
(on Windows 10) or Settings → System → Storage → Advanced storage settings → Backup options (on
Windows 11), and turn on "Back up using File History." Select the external drive as the destination.
File History runs every hour by default. It preserves multiple versions of each file, so you can
recover a version from before a mistake, not just the most recent. This is the "different media"
part of the 3-2-1 rule, and it satisfies one copy on its own.
Free method 2: Time Machine on macOS
macOS includes Time Machine, the equivalent tool. It also requires an external drive. Once set up,
it runs hourly and keeps local snapshots on the drive, letting you restore specific files or the
entire system.
Setup: plug in an external drive, open System Settings → General → Time Machine,
click "Add Backup Disk" or "Select Backup Disk," and choose the drive. Time Machine will format it
(if it is empty) and begin the first backup automatically.
Time Machine's strength is that it preserves history: you can restore a file from three months ago,
not just yesterday. This is more useful than a simple mirror backup, because most accidental losses
are "I deleted this and didn't notice for a week."
Free method 3: manual copy to an external drive
If you do not have an external drive, or the built-in tools do not fit your setup, a manual copy is
still a valid backup. Copy your important folders — Documents, Desktop, Downloads, any project
folders — to a USB drive on a schedule. It is less convenient than File History or Time Machine
because it does not run automatically, but it achieves the same thing if you remember to do it.
A reasonable cadence: monthly for personal files, plus before any major project deadline. The
downside is that manual copies are easy to skip, which is why automated tools are worth the setup
effort if you have the drive.
Free method 4: use your existing cloud storage, deliberately
If you have a Google Drive, OneDrive or Dropbox account with free space, you can use it as a
secondary copy for specific folders. The key is to configure it as a backup, not as sync:
Do not sync your whole Documents folder and delete things carelessly — the deletions propagate.
Do copy important folders to a folder inside the cloud service that you do not edit in place. This is closer to a backup because changes to the original do not propagate.
Or use the service's own versioning and trash — Google Drive keeps deleted files for 30 days, OneDrive for 30 days. Useful for short-term recovery, not long-term preservation.
This works for a small-to-moderate amount of important data. It is not a complete backup strategy,
but for a folder of tax records or a small project, it is a genuine second copy at no cost.
Free method 5: Google Takeout for cloud data
If your "backup" is really data stored in a Google account — emails, drive files, photos,
calendar — Google Takeout lets you export it all as a downloadable archive. You can schedule
exports to run periodically and save them to an external drive.
The export is not a running backup — it is a point-in-time snapshot. But scheduling a monthly or
quarterly Takeout and saving it locally gives you a genuine second copy of your Google data. This
is particularly useful for anyone whose primary email or cloud storage is a Google account.
If you have to buy one thing: a 1 TB or 2 TB external drive costs a fraction of
what cloud storage subscriptions add up to over three years, and it is the single most useful
piece of hardware for a home backup setup. File History and Time Machine both work well with one.
This is the one place where the honest answer is "the free methods have limits, and this is the
£60 to £80 that solves most of them."
5. Testing the backup (the step everyone skips)
A backup that has never been restored is a belief, not a backup. The only way to know whether your
backup works is to restore something from it. This is worth doing once, and then once a year
after that.
The test is simple: pick a file you have backed up, delete it from the original location, then
restore it from the backup. Check that the restored file opens correctly and has the content you
expect.
On Windows File History, this means opening File History, browsing to a version, and clicking
Restore. On macOS Time Machine, this means entering Time Machine, navigating to the file's
location at an earlier date, and clicking Restore.
For phone backups, the test is harder because you cannot easily restore a single photo from
iCloud or Google Photos without affecting the cloud version. A reasonable test: pick a photo
you have backed up and confirmed exists in two locations, delete it from one, confirm it remains
in the other, then restore it and confirm both copies are intact.
What the test catches: the external drive that is no longer connected, the cloud account that
filled up and stopped accepting uploads, the backup that has been running but backing up the wrong
folder because you changed where your files live. These are all real failure modes that you
cannot detect without trying a restore.
A related practical check: is your backup actually running? Most backup tools show a last-run
timestamp. If File History says "last backup 47 days ago," it is not doing what you think it is.
Checking this monthly is worth the five seconds.
This connects directly to the earlier guide on
why your phone is slow —
one of the common causes is storage nearly full, and backup tools that stop working when storage
fills up are part of the same problem.
Where this leaves you
Backing up does not require a subscription. It requires a second copy of your important data, on a
different medium, ideally with a third copy somewhere else. On a phone, that means Google Photos
or a monthly import to a computer, plus occasionally copying to a drive. On a computer, it means
File History or Time Machine with an existing external drive, or a manual copy if you do not have
one.
The most common failure is not a technical one. It is the belief that a cloud sync service is a
backup. Configuring any one of the methods above to run alongside the sync is enough to change
that.
The second most common failure is never testing the backup. Five minutes of restoring one file
once a year is the difference between a backup and a hope.
Frequently asked questions
Is iCloud a backup?
Partially. iCloud backups of your device settings, app data and messages are genuine backups that
can restore a new device to a previous state. iCloud Photo Library, however, is sync — deletions
propagate, and photos taken since the last sync are not protected. The 5 GB free tier is not enough
for full device backups including photos.
Is Google Photos a backup?
It is primarily sync. Deleting a photo from your phone removes it from Google Photos as well. Google
Photos does have a 60-day trash bin that preserves deleted items for recovery, but this is a
recovery feature rather than a backup strategy. For a genuine backup, use Google Photos alongside a
second copy elsewhere.
How often should I back up?
Depends on how much you would lose. For personal photos and documents, monthly is a reasonable
minimum. For active project work, weekly. Automated tools (File History, Time Machine) run hourly,
which is effectively continuous backup. The right cadence is the one that matches how much data you
would be willing to lose.
Do I need to back up my whole computer?
Not necessarily. Much of what is on a computer is either easily replaced (apps, downloaded media)
or already elsewhere (data in cloud services). Focus the backup on the folders that contain files
you created and cannot recreate — Documents, Desktop, project folders, and any local copies of
important data.
What is the 3-2-1 backup rule?
Three copies of your data, on two different types of media, with one copy stored off-site. It is the
standard minimum for anything important. In a home context: the original on your device, a local
backup on an external drive, and a copy in the cloud or on a device at another location.
Can I use an external hard drive as my only backup?
Yes, but a single external drive fails the "3-2-1" test on its own. Drives fail, and a backup on
the only copy of the drive is not a backup. Use the external drive as one of the copies, not the
only one. If you have limited options, an external drive plus a cloud service is a reasonable
minimum.
How do I back up my phone without a computer?
Use a cloud service — Google Photos with "Storage saver" quality is the most practical free option.
Alternatively, use the partner-sharing feature of a cloud service to share with a second account
you control. Both are forms of sync, so pair them with a periodic manual check or an occasional
import to a computer when you have access to one.
What is the most important thing to back up?
Photos and personal documents. They are the data that cannot be recreated. Everything else — app
data, messages, settings — matters but is either recoverable or replaceable. When in doubt, protect
the things you would be upset to lose, and let the rest go.
Sources and further reading:
Microsoft Support documentation on File History (Windows 10 and 11);
Apple Support documentation on Time Machine and iCloud Photo Library;
Google Photos Help documentation on backup, storage quality, and trash retention (60 days);
Google Takeout public documentation;
Apple Support documentation on iCloud storage tiers and iCloud Backup;
Google One storage limits and sharing;
general 3-2-1 backup rule references (originally popularised by photographer Peter Krogh in
The DAM Book, widely adopted as an industry standard).
Free-tier storage limits are accurate at the time of writing but do change — re-verify before
relying on a specific size. The article does not quote specific prices for external drives because
they vary by region, capacity and retailer.
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