Not Enough iCloud Storage for iPhone Backup? Check Next Backup Size First

If your iPhone says there is not enough iCloud storage to complete a
backup, do not start by deleting photos. First, go to Settings → [your
name] → iCloud → Storage or Manage Account Storage → Backups → This iPhone
and compare Next Backup Size with your available iCloud storage. Once you
know the shortfall, you can exclude only unnecessary app data, remove a
confirmed old-device backup, upgrade iCloud+, or use a computer backup.

The menu names in this guide follow Apple’s English-language iOS 26
documentation, checked on July 27, 2026. Apple lists iPhone 11 and later and
iPhone SE (2nd generation and later) as compatible with iOS 26. On an older
iOS release, Storage might appear as Manage Account Storage, but the same
Backups screen provides the size you need to compare.
See Apple’s iOS 26 compatibility list.

First, separate device storage from iCloud storage

Settings → General → iPhone Storage shows space on the phone itself.
Settings → [your name] → iCloud shows storage in your iCloud account. They
are separate. Your iPhone can have plenty of free local storage while its
iCloud backup still fails.

Deleting a local file also does not automatically add the same amount of free
space to iCloud. Apple’s
comparison of device and iCloud storage
explains that iCloud storage is shared by device backups, iCloud Photos,
iCloud Drive, and other iCloud data. Start with the iCloud usage bar, not the
iPhone Storage screen.

Compare Next Backup Size with the space available

Apple’s
iCloud backup troubleshooting guide
recommends checking the required backup size when the not-enough-storage alert
appears:

1. Open Settings, then tap [your name] → iCloud.
2. Check how much iCloud storage is already in use.
3. Tap Storage or Manage Account Storage.
4. Tap Backups, then select the iPhone you are using.
5. Wait for Next Backup Size to finish calculating. Apple notes that this
   can take a few minutes.
6. Subtract the current iCloud usage from the total capacity, then compare the
   result with Next Backup Size.

For example, if 2 GB is available and Next Backup Size is 5 GB, you need to
resolve a shortfall of at least 3 GB. If Next Backup Size is already smaller
than the available space, stop deleting data and check Wi-Fi, iOS updates, or
another backup error instead.

Choose the safest way to cover the shortfall

What you find	Best first option	Check before you act
An unused app has a large backup	Turn off backup for that app only	Confirm whether the app has its own sync or export method
A backup belongs to an old device you no longer use	Verify the device name, then remove the old backup	Do not confuse it with the current device or your only recovery copy
Most of the backup is data you need	Increase iCloud+ storage	Check the current plan and price shown on your device
You do not want to delete iCloud data or change the plan	Back up to a Mac or Windows PC	Confirm available computer storage and backup completion
Next Backup Size already fits	Troubleshoot Wi-Fi or software	Do not delete more data to solve a different failure

Option 1: Turn off backup for an app you do not need

On the current iPhone’s backup details screen, review the size for each app.
Only turn off an app if its data is disposable, can be recreated, or is
already protected by the app’s own account sync or export.

Apple says that turning off backup for an app stops backing it up and removes
that app’s existing backup information from iCloud. Do not disable backup for
messages, authenticator apps, game saves, notes, or work data until you have
confirmed exactly how that app can restore its information.
Review Apple’s iCloud storage management guidance.

Option 2: Remove only a confirmed old-device backup

The Backups list can contain an iPhone or iPad you no longer use. Compare the
device name and the backup date carefully, especially if the current and old
devices have similar names.

Deleting a backup also turns off iCloud Backup for that device. If it is the
only copy you could use for recovery, do not delete it until you have
confirmed that a newer backup or another recoverable copy exists.

Option 3: Increase iCloud+ storage for data you need

If the app data and old backups are all necessary, increasing iCloud+ storage
is safer than deleting data simply to make the warning disappear. Prices and
plans can change, so this article does not list them. Check the current
options on your iPhone and choose enough capacity to cover Next Backup Size
with some room for future growth.

Be especially careful with photos and files. When iCloud Photos is enabled,
deleting a photo on one device deletes it on other devices signed in to the
same Apple Account. Apple recommends archiving or copying important iCloud
data before deleting it.

Option 4: Use a computer backup instead

If you do not want to remove iCloud data or change your plan, you can back up
the iPhone to a Mac or Windows PC. Apple’s
comparison of iPhone and iPad backup methods
explains how computer storage differs from iCloud storage. Confirm that the
computer has enough free space and that the backup completes. Creating a
computer backup does not automatically remove or reorganize existing iCloud
data.

Run Back Up Now and verify the result

After you have covered the storage shortfall:

1. Connect the iPhone to a stable Wi-Fi network.
2. Go to Settings → [your name] → iCloud → iCloud Backup.
3. Make sure Back Up This iPhone is on.
4. Tap Back Up Now and stay connected to Wi-Fi.
5. Check that the date and time under Back Up Now update to the backup you
   just completed.

Apple’s
manual iCloud backup instructions
say to remain on Wi-Fi until the process finishes and to use the displayed
last-backup date and time to confirm completion. Automatic backups require
power, Wi-Fi, and a locked screen.

If enough space is available but the backup still fails

If Next Backup Size is smaller than the available iCloud storage, do not keep
deleting data. Apple recommends confirming the Wi-Fi connection, installing
available iOS updates, and trying another Wi-Fi network. If the backup is
taking unusually long, check the upload speed and leave the iPhone connected
to power and Wi-Fi for up to 24 hours.

If iCloud Backup is grayed out, check whether an iCloud restore is still in
progress. Also look under Settings → General → VPN & Device Management for
a management profile that restricts backup. On a company- or school-managed
iPhone, contact the administrator instead of removing a profile yourself.

Frequently asked questions

Does freeing iPhone storage also free iCloud backup space?

Not necessarily. iPhone storage and iCloud storage are separate. Removing app
data that is included in the backup can reduce Next Backup Size, but deleting
a local file does not automatically increase available iCloud storage by the
same amount.

Can I complete the backup without deleting photos?

Yes. Check Next Backup Size and the app backup list first. You might be able
to exclude a disposable app backup or remove a confirmed old-device backup.
If all of the data is necessary, consider more iCloud+ storage or a computer
backup instead.

Summary

When an iPhone backup reports that iCloud storage is insufficient, compare
Next Backup Size with the available space before deleting anything. Cover
only the actual shortfall by excluding disposable app data, removing a
verified old-device backup, increasing storage, or using a computer backup.
Then run Back Up Now and confirm that the latest backup time changes.