The following table contains the maximum attachment sizes in the most popular email services:
| Mail service | Maximum message size |
| webmail (HamaraHosting) |
25 MB |
| Gmail (If your Configured email in Gmail ) |
25 MB |
| Outlook 2010 to latest one | 20 MB |
| Thunderbird | 20 MB |
IF your incress the Outlook attachment file size follow bellow steps and change the size
Step1: Close Outlook and open the Registry Editor (regedit.exe)
press the start button and search the regedit.exe
Step2: Depending on the Outlook version, go to:
Outlook 2013 — HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Preferences
Outlook 2010 — HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences
Outlook 2007 — HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\PreferencesHKLM Outlook Preferences branch
In this branch find and edit MaximumAttachmentSize value, specifying the new attachment limit, e.g., 102400 (100 MB). By default, it is 20 MB (20480 KB). To completely disable the limit, change this value to 0.MaximumAttachmentSize - Outlook 2013
Note: take the backup of Outlook before the changes
Close the Registry Editor and restart Microsoft Outlook
How to send files greater than 20 Mb with Outlook 2013
If you need to send files greater than 20 Mb, you have solutions:
1.use the webmail
2. change the your Windows registry to increase the Outlook allowed max file size.
3. upload the file(s) to a file sharing or cloud service (such as DropBox, iCloud or SkyDrive) and email the download link instead of the actual files;
4. compress the file attachment using a compression utility like WinZip or WinRAR. Even better, so you don’t have to manually compress each attachment.
Please note that, even if you increase the max allowed file size from the Windows registry, it may be useless because a large file attachment will anyway be rejected by the mail server of the person receiving it. Most email servers allow between 10 and 30 Mb per incoming email.
