4 fast ways to trim the size of your mailbox

I admit it. I get busy working, and I never really pay attention to the size of my mailbox. That is, until I get a nasty little reminder from the system administrator saying I'm over the limit and need to delete some mail.

In hopes of changing my ways, I've decided to take a more proactive approach about managing my mailbox size. Here are a few things I've learned.

Who sets the limit?

First off, if you store your e-mail on a server, like a Microsoft Exchange server, your limit is probably set by a system administrator. Your Internet Service Provider (ISP) may also set a limit. The size limitations vary greatly, and can be anywhere from 1 megabyte (MB) to 90 MB or more. The consequences of reaching the limit are also subject to that administrator or ISP. They may send warnings, limit functionality, and at some point you may not be able to send or receive mail.

What exactly determines mailbox size?

Your main e-mail folder is the Inbox. That's where e-mail gets delivered. Your Inbox is located inside of your mailbox along with the other folders, such as Drafts and Sent Items, which are created by Outlook to store information. Knowing how much space is being taken up by these folders is your first step towards keeping your mailbox trim.

To check the size of your mailbox in Outlook 2003:

  1. On the Go menu, click Folder List.
  2. In the Navigation Pane on the left side of the screen, click Folder Sizes.

Image of how to see folder sizes in Outlook

You can now see the sizes of your mailbox and the e-mail folders inside it. Likely suspects for mailbox "bloat", besides your Inbox, include Deleted Items, Drafts, Outbox, and Sent Items. Boy, my mailbox definitely needed a trim!

4 quick ways to trim your mailbox right now

Tip 1: Look for the largest messages first and delete them

I never knew there was a way to group messages by size. This is handy because when you get those nasty administrator messages, you can probably delete a few of the largest messages, instead of wading through many smaller ones.

To group your e-mail messages by size:

  1. 1. On the View menu point to Arrange By and click Size.
  2. 2. Make sure Show in Groups (also on the Arrange By submenu) is selected.
  3. 3. Your messages will be sorted into groups such as Tiny (< 10 KB), Small (10 - 25 KB), and so on.
  4. 4. Delete messages marked "Large" first (or save the attachments elsewhere, see Tip 3 below) to make the greatest difference to your overall mailbox size.

Image of arranging e-mail by size

Tip 2: Empty your Deleted Items folder

Every time you delete an e-mail message, it goes into the Deleted Items folder. Since you probably meant to get rid of these deleted items in the first place, permanently tossing them out is a painless way to cut the bulk.

To delete these messages automatically, use the Empty the Deleted Items folder upon exiting setting.

To use the Empty the Deleted Items folder upon exiting setting:

  1. On the Tools menu click Options.
  2. In the Options dialog box, click the Other tab.
  3. In the General section, click the Empty the Deleted Items folder upon exiting check box.
  4. Click OK.

Image of how to empty Deleted Items folder

Tip 3: Save attachments outside your mailbox

Attachments take up lots of space. I've started saving them to a location outside my mailbox. To do this, on the File menu click Save Attachments while you have the e-mail message open.

Image of how to save e-mail attachments

Tip 4: Archive your Sent Items folder regularly

Generally, a copy of each message you send is stored in your Sent Items folder. It's easy to forget about this, and like me, you may end up with a huge Sent Items folder. Since you probably don't need to track each and every item you send, you can either delete these messages or archive them.

To specify archive settings for AutoArchive, right-click the Sent Items folder, click Properties, and select the AutoArchive tab.

To archive manually, on the File menu click Archive and scroll to select the Sent Items folder.

The steps above are a good start, but there's a lot more you can do in terms of ongoing mailbox management. It's a good idea to regularly archive your messages, not just in your Sent Items folder, but in your entire mailbox. Also, you may want to check out the Mail Cleanup Tool.

Well, at least for now, my mailbox is feeling a little leaner. If I keep up the good work, the system administrator will need to find someone else to pick on with those nasty little reminder messages.

—Laurie Pritchard

Comments (25)

  1. I provide IT support to our Intelligence Directorate in our agency.  When users start running up against the mail storage limit (warning at 75 MB, restricting sending at 100 MB), I first review their auto-archive settings.  Then I work with users to remove attachments from messages by first saving them to a folder, then editing the message to delete the attachment, and write a statement as to where the attachment is saved, possibly even a UNC to the folder.  Then save the message to an Outlook folder.

  2. JAMES BOYD says:

    I think these are good for all involved using a computer.

  3. GIRSH says:


  4. At my work location I do not have the "View", "Arrange By" option.

  5. Judy says:

    Is there a way to slim mailbox by copying folders to a disc and if so how?

  6. thadamae@earthlink.net says:

    i dont have the "view" – Arrange by Size option…..how do i get it ??? is there an "outlook-express" update ?  

  7. Laxmi says:

    Generally there will be long threads of email going on some topic.  The latest thread would most probably contain the whole story.  So, delete all the prior mails of the thread by using ‘Find Related Messages’ option.

  8. Feroz Bakht says:

    Nice tip, keep it up

  9. Owen Zhang says:

    utilize the rule to move the mail to your private folder by your proactive setting

  10. John Waugh says:

    One other thing many forget to do is to make a selection in your setup to remove their mail from the server when opened.  I know of some friends who could not send mail because they were over their limit, deleted a bunch of e-mail and still had problems; this was because the mail was not being removed from the server when it was opened.  For Judy wanting to copy folders to disk, can be done but not practical, Owen Zhang has the better solution in using Personal Folders, in addition do a Daily Archive of your Outlook makes recovery of important files easy.

  11. Brandon Forman says:

    I created an outlook rule to increase the font size of the subject line for any mail over 100kb. This helps me quickly spot large mails that push me across the fine line I walk at my mail box limit.

  12. veeraj saini says:

    this is good article. now a days, like in outlook 2003, you can maximize the size of pst file upto 20GB. Sounds Good!!

  13. Peter Murr says:

    I would like to find out how to increase the size of the "Blocked Addresses" section.  So that I can keep the same people from continually sending e-mails over and over again.  For instance, on yahoo, I’ve got over

    500 e-mails from "geocities" alone.  That’s the limit.  I waste an hour a week just deleting e-mails, there isn’t any reason, those people just figure it’s free, why not just keep sending.  

  14. Denton Yoder says:

    Too bad we can’t easily export to an access database, and burn to CD.  You can drag and drop messages in a folder, but it needs the date-time stamp added into the filename to make them uniquely named.

  15. RSmitty says:

    I added the size column to my views which keeps the size of each email in mind.  Then once a week, I click on the size column to sort by largest size first, then I review and delete where possible.

  16. M. Spencer says:

    Brandon, I’d love to know how you got it to increase the font size.  Thanks!

  17. Graham says:

    Given the cheap cost of storage these days, it’s a little ridiculous forcing mailbox size limits on users.   Just shove another pair of 500GB disks into the server.

  18. Ron Ruosch says:

    This tip seems appropriate mainly for email systems that house ALL messages "on the server."  Using a mail client (Outlook, Ooutlook Express, ect.) with an ISP generally involves the periodic downloading of messages onto the client machine for local storage either in the "local" inbox or in custom folders.  The only limit other than your local hard drive capacity is that imposed by the ISP for storage on the SERVER.  As one commenter mentioned, people sometimes leave messages on the server which is a common way that INBOX limits get exceeded.  Most people have no reason to leave messages on the server, so simply verifying that your email client deletes them from the server once retreived (NOT to be confused with READ).  Once the mail is on the local machine, the user has no limit on storage.

    Still, the other tips can be helpful.  The Deleted Items folder should be purged often.  Outlook Express can be made to do this automatically at shutdown.  The sent items should be moved into folders they are connected with just as you would with paper coorespondence.  Archiving all sent messages as a group seems awkward to me.

    To review status of an email exchange, I go to the subject folder wherein I find ALL messages, both inbound and outbound (Sent).  Another commenter mentioned that follow up messages often have copies of previous messages included.  Sometimes you only need keep the last message in a thread to have the whole story.  Again, this is a much easier determination to make if you are reviewing just those messages in one specific folder (one subject).

    Finally, if you lose track of a message, either because you misfiled it or can’t remember if you sent a reply, then you use the ‘FIND’ function to serach your entire mailbox.

    I may have gotten off track a little here, but it seems to me that an efficient user of ANY email system on ANY server should never have to worry about a STORAGE LIMIT.  In the paper world if your INBOX is overflowing and can’t hold the papers on your desktop, you need more help than a tip that says "you need to delete some stuff."

  19. Will download paper now and will let you know after I read all of the materials.  Thanks

  20. Jerry Carroll of Misawa says:

    No need to save or archive to a CD really.

    And by the way, this is about Outlook, not Outlook Express.

    create a personal folder


    Email Accounts

    change existing account

    new outlook data file

    click OK




    Then just move all your e-mails that you don’t want on the server there.  Just remember, that once it is on the PC, it is not accessable when you go to another PC.  Only Items that you need to access from any PC on your domain (or via VPN) should stay on the server.

  21. Brian says:

    If I archive my e-mails every so often.  How do I find those files when I want them again?

  22. Allan Warrior says:

    For those with versions of Outlook that don’t have a "View–>Arrange By–>Size" option, you can easily sort the contents of your mail folders using the Size column header. Click it once to sort from smallest to largest, and twice to sort from largest to smallest.

    When you’re done with clean up, click the Received header to return to the original sort.

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