DB LabsQuick Answer
The fastest way to clear Mail storage is to delete and re-add your email account: go to Settings > Mail > Accounts, select the account, tap Delete Account, then add it back. This clears all cached data and can free up 1-5 GB. Your emails are not lost — they re-download from the server (IMAP). For less drastic options, delete emails with large attachments, empty Trash and Junk folders, and reduce Mail Days to Sync.
Check How Much Mail Is Using
Before clearing anything, check the actual storage usage:
- Go to Settings > General > iPhone Storage.
- Scroll down to find Mail in the app list.
- Tap it to see the total size — the app itself is small (around 30 MB), but Documents & Data can be several gigabytes.
If Mail shows more than 1 GB, you will benefit significantly from cleaning it up.
Method 1: Delete and Re-Add Email Account (Most Effective)
This is the nuclear option but also the most effective. It clears all cached email data in one step.
1 Note Your Account Details
Before deleting, make sure you know your email address and password. If you use two-factor authentication, you may need an app-specific password (for Gmail, Outlook, etc.). Write these down or save them in your password manager.
2 Delete the Email Account
Go to Settings > Mail > Accounts. Tap the email account you want to clear. Tap Delete Account at the bottom and confirm. This removes all locally cached emails and attachments.
3 Re-Add the Account
Go back to Settings > Mail > Accounts > Add Account. Select your email provider (Google, Microsoft, Yahoo, etc.) and sign in. Your emails will re-download from the server, but only the most recent ones based on your sync settings.
4 Reduce Sync Period
After re-adding, go to Settings > Mail > Accounts > [your account] > Mail Days to Sync. Set this to 1 Week or 2 Weeks instead of "No Limit" to prevent the cache from growing back quickly.
Method 2: Delete Emails with Large Attachments
If you prefer not to remove the entire account, target the biggest storage offenders — emails with large attachments.
1 Search for Large Emails
Open the Mail app and go to the inbox of the account using the most storage. Tap the search bar and type "attachment" or filter by size if your email provider supports it.
2 Delete Emails with Attachments
Look for emails with large photos, PDFs, presentations, or video files attached. Swipe left on each and tap Trash. Focus on the oldest and largest messages first.
3 Empty the Trash
Go to the Trash folder in your mailbox. Tap Edit > Select All > Delete to permanently remove the trashed emails and free up space immediately.
Method 3: Empty Junk and Trash Folders
Junk and Trash folders accumulate emails with attachments that continue using storage.
- Open Mail > Mailboxes > Junk. Tap Edit > Select All > Delete.
- Open Mail > Mailboxes > Trash. Tap Edit > Select All > Delete.
- Repeat for each email account if you have multiple.
Method 4: Switch to Fetch Instead of Push
Push email constantly downloads new messages and their content, growing the cache faster. Switching to Fetch reduces how aggressively Mail downloads data.
- Go to Settings > Mail > Accounts > Fetch New Data.
- Turn off Push at the top.
- Set the fetch schedule to Every 30 Minutes or Manually.
- For each account, tap it and select Fetch instead of Push.
This also helps with battery life since your iPhone checks for new email less frequently.
Prevent Future Mail Storage Buildup
- Set Mail Days to Sync to 1-2 weeks: Settings > Mail > Accounts > [account] > Mail Days to Sync.
- Unsubscribe from newsletters: Marketing emails with images contribute to cache growth.
- Use a web browser for email: If you rarely need the Mail app, check email through Safari (gmail.com, outlook.com) instead — this uses zero local storage.
- Consider a third-party mail app: Apps like Gmail, Outlook, or Spark often manage their cache more aggressively than Apple Mail.
For a comprehensive storage cleanup, see our complete iPhone storage guide or learn what is taking up storage on your iPhone.