Gmail Storage Full: How to Fix It

Try these in order

1. Understand what's actually full. A personal Google Account gets 15 GB shared across Drive, Gmail and Google Photos — plus things like WhatsApp backups — so a full "Gmail" is often really a full Drive or Photos (Google Help).
2. Empty Trash and Spam first. This is the quickest way to recover space, because items sitting in Trash and Spam still count against your limit until they're permanently cleared. Empty Gmail's Trash and Spam, plus the Drive and Photos trash (Google Help).
3. Delete a few emails with huge attachments. Google specifically recommends finding one or two messages with very large attachments you no longer need: tick the box beside each message and click Delete at the top, then click Empty Trash now in the banner (Google Help).
4. Give the storage figure time to update. After a big cleanup, wait — if your account still shows as full after 30 minutes you can move on to advanced cleanup, and deleting many files at once can take 48–72 hours to reflect (Google Help).
5. Trim your WhatsApp backups if you're on Android. They count toward your Google storage. In WhatsApp go to Settings > Chats > Chat backup and turn off Include videos first — otherwise a new backup just reappears — then delete old backups at one.google.com/storage/management (Google Help).
6. Use Google One's storage manager for a guided cleanup. Google One lets you clear space across your account and shows large or unwanted files in one place (Google One Help).
7. Buy more storage if cleaning isn't enough. Google One is a subscription that raises your total storage across Drive, Gmail and Photos depending on the plan you pick (Google Help).