If you back up your Mac, iPhone, iPad or iPod touch data to iCloud, it’s a good idea to check how much available storage space you have left. By default you get 5 GB space for free, then after that you can purchase additional space. Here’s how to check the amount of space being used from your iPhone.
Check iCloud Space from iPhone
First tap on Settings on the home screen.
Next scroll down and tap iCloud.
Under iCloud settings tap Storage and Backup.
On the next screen you’ll see the total space as well as available space. You can even buy more space by tapping on Change Storage plan if you want to. Here you can also turn on automatic backup it it’s not already enabled.
If you’re a Windows user, make sure to check out how to make iCloud work on your PC.