What happens if I leave iCloud full?

Backups stop running and new photos stop syncing to iCloud. The phone works as normal, but every photo you take from now on exists only on the phone. That is the point at which losing something becomes possible.

Does clearing iCloud free up space on the phone?

No, they are two separate spaces. iCloud is room in the cloud, iPhone Storage is room on the phone. They only affect each other through Optimise iPhone Storage, which lets the phone keep smaller versions of photos held in iCloud.

Can I delete an old backup?

Yes, backups of phones you no longer own can be removed and often free several gigabytes. Never delete the backup of the phone you are using right now. The device name is shown at the top of the list under Backups.

What does more storage cost?

Apple sells iCloud+ with 50 GB for a small monthly amount, with larger plans above that. It is usually cheaper, and considerably safer, than spending an evening deleting photos you later wish you still had.

iCloud storage full? Free up space without losing photos

Every Apple account gets 5 GB of iCloud for free, and that rarely covers a phone that backs up its photos. When the space runs out, backups and photo syncing stop quietly, with nothing on screen to tell you. It takes about fifteen minutes to sort out, and there are two routes: clear space, or buy more.

Start by seeing the breakdown. Open Settings, tap your name at the top and choose iCloud. The bar at the top shows how much Photos, Backups, Documents and Mail are using. Tap Manage Account Storage for the details.

Try this first

Empty Recently Deleted in Photos. Open Photos > Albums > Recently Deleted and choose Delete All. What you already deleted stays there for 30 days and takes up space the whole time, both on the phone and in iCloud. After emptying it, those photos cannot be recovered.
Go through your videos. Photos > Albums > Videos. A few clips from one holiday often use more space than all your still photos together.
Remove old backups. Manage Account Storage > Backups. This is usually full of copies of phones and tablets you no longer own. Delete the devices you do not have any more, but never the backup of the phone you use today.
Look inside that same backup for apps you do not care about and switch backup off for them. Games and streaming apps often take more than they need.
Clear Mail in iCloud if you have an icloud.com address. Large attachments and old newsletters count towards the same space.
Go back to the iCloud page and see whether the bar has got shorter. Once you have freed a gigabyte, the backup usually runs by itself the following night.

If that did not help

Buy more space. Settings > your name > iCloud > Upgrade to iCloud+. 50 GB is enough for the vast majority and costs less than a coffee a month.
Or move your photos somewhere else. Connect the iPhone to a computer with a cable and copy them over, or install Google Photos on the phone and let it back up there instead. Google gives you 15 GB free.
If you copied the photos to a computer, open a dozen of them there and check they display before you delete anything from the phone.
Check the result. Go to Settings > your name > iCloud > iCloud Backup and read the date under the button. Today's date means everything is running again.

Do not switch iCloud Photos off without knowing where the originals are. If you are asked what should happen to the photos, choose Download Photos and wait until the download finishes. Choosing Remove from iPhone can lose them for good. If you are unsure where your photos actually live, or whether the backup has been working lately, write to us before you change anything. Photos are what people most often lose and never get back.