Why won’t it let me backup my phone? It says I don’t have enough iCloud storage though I’m only using 13.4MB out of 5GB. I’ve already went into my iCloud and it’s empty.

HI there Kalagni, welcome to Apple Support Communities I understand that you're having difficulty backing up your phone, and I would be more than happy to help you out with that. Since backing is crucial and ensures that data loss never occurs, it's important to note that your phone will back up almost every single megabyte when you back it up to iCloud (you can also back up using a computer too). What is most likely occurring is that your phone has more data on it than the amount of iCloud space that comes with your Apple ID. To check the storage of your iPhone, go into settings > general > iPhone storage and looks at the total GB on your phone. If its over 5 gb you're gonna need to either back up to your computer using the Finder or iTunes, or purchase more iCloud storage before you can back up!

I hope that helps. Check out this article for more information also, and always feel free to reply to this post if you have any more questions! You can also contact Apple Support for help if you ever need it!

-Big_Tex

*edit: corrected the spelling of 'general'

What Big Tex is saying is, you may only be using 13.4MB out of 5GB of iCLOUD STORAGE. But when your phone backs up, what is on your phone, which is probably more than 5GB. So, if you go into settings, then general, then iPhone storage, and check the IPHONE STORAGE, you will probably see that you have more than 5GB of data on your phone. Your phone storage will be “X”GB out of 64GB, 128GB or 256GB. And depending on how you have iCloud set up, will depend on what the phone backs up (photos & messages for example) & saves to iCloud.

What does iCloud back up? - Apple Support

Yes, but how many gb of data is there on your iPhone? Use this to find out.

-Big_Tex

You’re welcome 😊