Mail Taking Up Storage on iPhone? How to Shrink It Without Losing Email

You open Settings > General > iPhone Storage to see why the phone is full, and Mail is near the top at several gigabytes, even though you hardly keep any email. That number is the copy of your messages, attachments and images that the Mail app has saved on the phone. iOS has no button to clear it. Two things do shrink it: delete the Mail app and reinstall it, or remove the bloated account and add it back. Before either one, make sure that account keeps its mail on the server, and then delete the bulk mail at the server so the space doesn't fill up again.

1. See how much Mail is really using

1. Open Settings > General > iPhone Storage and wait a few seconds for the list to finish loading.
2. Find Mail in the list and tap it. The size shown includes the app and the data it keeps on the phone.

Under a gigabyte is normal for someone with a couple of accounts, and it usually isn't worth the trouble. Several gigabytes usually means years of attachments, or an account you stopped using long ago that still syncs. If you read email in the Gmail or Outlook app instead, that app shows up under its own name in the list, and the steps below work the same way, except you'll have to sign in again.

2. Check that your mail is on the server first

This takes one minute and is the step that keeps you from losing anything. Open a web browser and sign in to your webmail: gmail.com, icloud.com/mail, outlook.com or your provider's site. Search for an old message you can also see on the phone, and look in Sent too. If both are there, the phone only has a copy, and you can go on.

If something on the phone is not in webmail, that account may be POP: older setups download each message and can remove it from the server. Don't delete the app or the account. Ask your email provider how to keep the mail first, or forward the messages you need to an account that keeps mail on the server. Also send or copy any unfinished drafts before you start.

3a. Delete the Mail app and reinstall it

This clears the downloaded copy for every account at once. Apple lets you delete Mail, as one of the built-in apps listed in Delete built-in Apple apps, and its iPhone User Guide says deleting an app "removes it and its data from your iPhone."

1. Touch and hold Mail on the Home Screen or in App Library.
2. Tap Remove App, then Delete App, then Delete.
3. Open the App Store, search for Mail (by Apple), and download it again.
4. Go to Settings > Apps > Mail > Mail Accounts and check that your accounts are listed and that Mail is turned on for each one. Apple doesn't say whether accounts stay through a delete and reinstall, and its built-in apps page says deleting an app also deletes "related user data and configuration files," so don't assume. If an account is missing, tap Add Account there and sign in again, so have your passwords handy before you start.
5. Open Mail and give it time on Wi-Fi to sync.

Apple notes that the free space can take a moment to show up after you delete an app. Mail downloads your mail again once it's back, so the size climbs a little, but it shouldn't return to the old total unless your inboxes are still huge. Step 4 deals with that.

3b. Or remove one account and add it back

Use this when one account is the problem, like an old work address or a mailbox you never clean, or when you no longer use an account at all. In that case, just remove it and don't add it back. Apple's steps (Add and remove email accounts):

1. Go to Settings > Apps > Mail > Mail Accounts, then tap the account.
2. Tap Delete Account. For your Apple Account's iCloud Mail, this button says Sign Out, and signing out affects much more than Mail, so use 3a for iCloud instead.
3. To add it back, return to Mail Accounts and tap Add Account.

According to Apple, this removes the account "from the Mail app and from all the apps that use it on your iPhone." Contacts, calendars and notes that belong to that account disappear from the phone until you add it back. They stay with your provider, and the email account itself isn't closed.

4. Delete the bulk mail on the server so it doesn't come back

Reinstalling only removes the copy. If your inbox still has 40,000 store emails and newsletters, Mail keeps saving copies of them as it syncs. The lasting fix is to delete the mail you'll never open where it actually lives, at the provider.

• Find the big ones. In Gmail, search larger:10M to list messages over 10 MB. Keep anything you haven't saved elsewhere, like signed documents, photos people sent you or tax paperwork.
• Clear promotions and newsletters in bulk. Each one is small, so attachments matter more for space, but clearing thousands of them means Mail has far less to save again. Our Black Friday email guide shows how to keep receipts and tracking emails while deleting the rest, which matters in late November.
• Empty the Trash. Deleted mail sits in Trash until the provider purges it. Gmail permanently deletes Trash after 30 days (Gmail Help). Other providers set their own schedules, and you can empty it yourself sooner once you're sure.

Deleting thousands of emails one screen at a time is the slow part. Phone Diet's email cleaner connects to Gmail, iCloud Mail, Outlook, Yahoo, AOL or any IMAP account, groups newsletters and promotions, and moves the ones you pick to the provider's Trash, so you can restore them if you change your mind. If an account has no Trash folder, it tells you the delete is permanent before it runs.

What Phone Diet can't do here

We make Phone Diet, so to be plain about its limits: it can't clear the Mail app's saved copy. iOS doesn't let any app reach another app's data, so the only ways to do that are steps 3a and 3b above. Phone Diet works on your mailbox at the provider, which shrinks what Mail has to download again. It also can't rescue POP mail that exists only on the phone. Scanning your inbox and your first cleanup are free; cleanups after that, Quick Clean and unsubscribing from Gmail lists in the app are part of Premium. If your mailbox is already tidy and Mail is just big from cached attachments, you don't need an app at all. Delete and reinstall Mail and you're done.

Common questions

Is there a way to clear the Mail cache without deleting the app?

Not from Settings. iOS has no "clear cache" option for Mail. Deleting and reinstalling the app, or removing and re-adding an account, are the two ways to drop the saved copy.

Will deleting the Mail app delete my emails?

Not for accounts that keep mail on the server, which covers iCloud, Gmail, Outlook and Yahoo when they're set up the usual way. It only removes the copy on your iPhone. Check webmail first (step 2) to be sure, especially for old POP accounts.

Why is Mail big again a week later?

Mail saves messages and attachments as it syncs and as you open them. If the mailbox on the server is still huge, the copy grows back. Delete bulk mail at the provider (step 4) and empty the Trash.

Is Mail only one part of a full phone? Start with what's taking up space on your iPhone, and for the Messages app, which fills up in a similar way, see how to delete old text messages.