Ipad won’t backup to iCloud depite enough space

I have to ask what might be an obvious question - as some confusion between available storage types locations have been observed amongst many users that have asked similar questions in the past. I quite understand you reticence in attempting upgrade from one major version to another without having a precautionary iCloud or iTunes backup.

Are you confusing available iCloud storage with the “on-device storage” of your iPad?

iCloud

Settings > [Your Name / AppleID] > iCloud > Manage Storage - verify reported used and spare space.

iPad (on-device)

Settings > General > iPad Storage - verify reported used and spare space.

Now, having hopefully cleared-up any confusion if it exists (I respect that you may in fact be fully aware - but past questions within the community suggest that the question must be asked), lets establish if we do in fact have adequate space for the backup.

Settings > [Your Name / AppleID] > iCloud > Manage Storage > Backups > [This iPad]

Now, check the Backup Size and Next Backup Size - the sizes of both will depend upon the last backup (if it exists) and the amount of data required for the next incremental backup. You must have at least the amount of iCloud free space to accommodate the Next Backup Size. Ideally, I would recommend that you try to maintain at least the amount of free space for a full backup (i.e., Backup Size + Next Backup Size).

Remember that you initial “free of charge” 5GB iCloud storage is quite limiting - and is often inadequate for backup of a device in regular use. Consider also that your iCloud space is shared with other services (such as synchronised data libraries for native Apps, email and Messaging etc.). Many users often need to opt for a least the first “paid” tier of iCloud Storage (50GB) - sometimes more.

I hope this information is helpful to you, if only in helping you to check that you do in fact have adequate iCloud space for your needs. Hopefully this will identify any storage issues that are inhibiting your ability to backup to iCloud.

If you have access to a PC or Mac, you could also consider creating an iTunes backup - for security - prior to making the leap from iOS12 to iPadOS13.x.

Do let us know how you get on - and any ongoing issues, with detail, that you might still have.

You haven’t been able to provide any indication of the space required for the backup - but, given you have now confirmed that you are trying to backup to the meagre 5GB of free iCloud storage (that is shared with other Apple services), I strongly suspect that you have insufficient iCloud storage to complete the backup.

The free space on your iPad is essentially irrelevant - unless you have no data worth preserving to a backup.

If you’re unable to provide a usable payment method to use core paid Apple services, upon which you depend, you perhaps have bigger problems.

In the circumstances, I suggest that you contact Apple Support for help - who may be able to provide more appropriate advice and direct assistance. You’ll find the link to Contact Support at top-right of this page.

You may not be eligible for free support from Apple, but you can still raise a “paid” support case. Sometimes we have to take this route, accepting that free support is unavailable or appropriate. Whilst help provided here, within ASC, costs you nothing (our assistance is voluntary), sometimes you’ll need to seek help directly from Apple if something needs to fixed that we cannot resolve - for example, resolving a back-end issue with your account.

Anyhow, lets continue with trying to help insofar as we can...

Now that you have upgraded your iCloud storage to the first paid tier, unless you iPad is chock-full of data, you should now have adequate iCloud storage to support your iPad backup. If you still have difficulties backing-up, your should force-restart your iPad:

https://support.apple.com/en-gb/guide/ipad/ipad63d30b5a/ipados

Are you experiencing any other connectivity issues - other services not working, or no access to webpages?

Next, assuming you are attempting this from your home broadband, restart you Home Router. Disconnect power, wait 30 seconds, then restart the router. When the router has finished its reboot (this may take many minutes), again force-restart your iPad - then try to backup again.

If none of this helps, try to connect to a different WiFi network; even a WiFi hotspot from you phone will suffice.

Good, I’m delighted that we have finally resolved the issue.

You have also demonstrated that your initial “free” 5GB iCloud storage was totally inadequate to backup your iPad.