apple’s mail app doesn’t provide much control over the amount of storage it uses. you want to download and store a large number of emails so they can be indexed and searched with spotlight. but the mail app can sometimes use a lot of space, which is particularly burdensome on 16gb iphones with limited storage.
this is similar to the problem with the mail app on a mac. On both iOS and OS X, the Mail app can take up gigabytes of storage space because you want to store a complete offline copy of your email.
see how much space mail is using
related: how to free up space on an iphone or ipad
You can see how much space the Mail app on your iPhone or iPad is using the same way you would see how much space any other app is using. open the settings app on your device and go to general > icloud storage and usage > manage storage. scroll down the list and find the mail app. this shows how much space is used by “mail and attachments”.
The only option here is “open mail”, which only opens the mail app. there is no useful way to reduce the amount of space used by the mail application. you have to do it by other means.
the bad solution: manually delete the emails
Related: How to stop your Mac’s Mail app from wasting gigabytes of space
If you’re feeling particularly masochistic, you can do it the old-fashioned way. just open the mail app and start deleting emails, especially emails with attachments. select the emails, tap “move” and move them to the trash. be sure to empty the trash afterwards.
To search for mail with attachments, you can touch “mailboxes” to open the mailbox list, touch “edit”, enable the “attachments” mailbox, and search for emails with attachments. they will probably be larger and take up more space.
You probably don’t want to do this! Any email you delete from your phone will be deleted from the server if you use imap for your email, which you probably do. even if this wasn’t a problem, this would take a long time. there is also no way to remove an attachment from an email; just delete all email.
a better solution: delete and re-add the account
There is a better solution. You can force your iPhone or iPad Mail app to start fresh and discard all those offline copies of emails by deleting your current email accounts and adding them back.
Assuming you’re using imap or exchange for your emails, you won’t actually lose any emails if you do this. they will still be stored on your email provider’s server and can be accessed by logging in from the web. however, if you are using the older pop3 protocol, those emails can only be stored on your device. however, unless you know otherwise, you’re probably using imap or exchange.
To do this, open the settings app, tap “mail, contacts, calendars” and tap your email account name. tap “remove account” to remove the account from your device. make sure you have the email account username, password and server details before doing this! if you don’t, you won’t be able to add the account again later. if you have multiple email accounts, you’ll want to delete them all from here.
then turn off your iphone or ipad and turn it back on to ensure all offline caches are fully cleared. open the mail app and you will be prompted to provide your email account details again. If you need to add additional email accounts, open account settings, tap “mail, contacts, calendars” and tap “add account”.
your iphone will start downloading emails again, but this will remove the previous buildup of cached emails and attachments.
a helpful tip: limit the number of emails your service provides to send
The above tips may not be good enough to reduce the space used by the mail application in the long run. Fortunately, there may be a way to prevent the Mail app from downloading all emails to your email account. unfortunately, there is no option in the mail app for this.
Your email service may provide an option that allows you to limit the number of emails you provide to imap clients such as the mail application. for example, if you use gmail, you can log in to gmail.com, open the settings page, click “forwarding and pop/imap” and enable the option “limit imap folders to contain no more than this number of messages “. set it to “1000” and the mail app will not be able to download more than 1000 messages from each folder it sees. other email services may have similar options – check their settings pages on the web to see.
To clear your download cache, you’ll want to remove and re-add your iPhone email account after changing this setting.
the only foolproof solution: use another email app
Unfortunately, the mail application can be difficult to master. It may eventually take up a lot of storage space again after removing and re-adding the accounts. Not all email services allow you to limit the number of emails that your email service displays to the mail application.
apple has not provided any option to control the amount of storage used by the mail application. however, you can always use another email app. For example, if you use Gmail, install the Google Gmail app from the App Store. if you use microsoft outlook.com or yahoo! mail, for example, then download the outlook or yahoo apps for ios. These apps will generally not attempt to cache a large number of offline emails, so they will use much less storage space. in fact, after using the gmail app for months, only 53.4mb of “docs and docs” are cached. data” on my iphone.
Once you set up your new email app, you can remove your email accounts from the built-in email app by following the instructions above, and it won’t download emails or use any space. if you want to keep syncing calendars and contacts with an account but not use it in the mail app, go to settings > mail, contacts, calendars, touch an account name and turn off the “mail” slider for that account. you’ll still have your address book and calendar, but email won’t take up space.
Unfortunately, Apple’s Mail app, on both mobile and Mac devices, doesn’t offer much control over the amount of storage it uses. the best solution may be to use another email application if this is a problem for you.
image credit: karlis dambrans on flickr