iCloud: Check your iCloud.com storage usage
You can use Settings on iCloud.com to see how much iCloud storage you have and how much is available. You can also see a bar graph that shows how much storage various categories of data use, such as iOS device backups, photos and videos, documents and data stored in iCloud, and email messages and attachments.
Go to Settings on iCloud.com, then look at the Storage section.
To get more information about a segment of the bar graph, hold the pointer over the segment until its name and numeric storage size appear above the graph.
If you run out of space, you can upgrade your storage. You can also manage your storage space by deleting backups of iOS devices you no longer have, backing up fewer iOS apps in iCloud, deleting photos or videos, deleting files stored in iCloud, or reducing email storage space.