Back up

Your next backup probably requires more than the free space you have left in iCloud.

So more than 2.5 GB extra.

Take a look at this article:

If you can't back up to iCloud or restore from iCloud backup failed - Apple Support

Here's how to find your Next Backup Size:

• On iOS 11 or later and iPadOS: Go to Settings > [your name] > iCloud > Manage Storage > Backups. Tap the device you're using.
• On iOS 10.3: Go to Settings > [your name] > iCloud > iCloud Storage > Manage Storage. Tap the device you're using.

Good luck!

Hi Ematrica,

Understand as per your question the above , when you try to back up you don't have enough iCloud storage .

The first 5GB is complimentary for using this services .

Next is to check for the storage that you have on your phone storage .https://support.apple.com/en-sg/HT201656

Then you can check for iCloud backup size as per Androish suggest.

Options here :

-1 you can choose to only back up certain information to iCloud

-2 you can purchase more storage for your phone back up.

Good luck!