Have you ever had trouble sending a large email attachment? If you try to send an attachment that is too big then you may find that it bounces back to you (ie you receive a message saying that the message could not be delivered). The limiting factor may be in the recipient’s email system or in a system that the email (with attachment) has passed through on the way to the recipient.

You are not likely to encounter this problem if you are just sending average-sized spreadsheets, word processing documents or pdf files, but “media files” such as video clips, sound files, and many high-resolution picture files can very easily be far too big to send as attachments.

Large AttachmentsHow do I know the size of an attachment? This depends on the email system you are using. In Hotmail, for example, after you have added the attachment to the email you can hover your mouse over the attachment and a small box will pop up that includes the file size (eg 273kb). With most other systems the size of the attachment is shown in brackets after the name of the attachment.

What is the maximum size of an attachment? Hotmail is supposed to be able to receive 10mb attachments, Yahoo and Gmail have a limit of 25mb. These are all webmail systems. If you are using POP-based email (eg you check your email using Outlook or Windows Live Mail) then there is probably a limit set by the email servers you are using. If you have your own domain name then you are probably using your domain host’s email servers. Otherwise, you will be using your ISP’s servers. The limit they impose can be as low as 5mb. Also, the theoretical limit of a Gmail attachment is 25mb but the actual file sent through cyberspace is larger than your original file by up to about 20% so Gmail’s actual maximum is probably nearer to 20mb. Anyway, even if you know the limits of your own system, that doesn’t help in telling you what your correspondent can receive as that depends on their system rather than yours. Personally, I would not assume that an attachment of over 5mb is going to go through without trouble. I always check with the recipient that they have received anything I have sent bigger than 5mb. Note: there are 1024kb in 1mb, so if your attachment size is expressed in kb rather than mb then anything less than about 5000kb is less than 5mb and will probably be delivered without problem.

What can I do if my attachment is too big? There are several options:

  • split the file up into smaller pieces. There is software available for splitting and rejoining files. I don’t recommend this method.
  • compress the file into a (smaller) zip file. This can work very well for some file types (eg tif files) but not have very much effect on others (eg jpg picture files, that are already optimised for the trade-off between size and quality). Zip files are a good idea, by the way, if you are sending many attachments as they can all be sent in one zip file for unpacking at the recipient’s end.
  • use an online service such as www.goaruna.com

Using GoAruna, you don’t even have to register if you just wish to send a single file. All you need to do is enter your own and the recipient’s email addresses and upload the file you wish to attach. The recipient is then sent an email with a link so that they can download the file. Although there is a time limit (seven days) on the availability of the download, this method does have the advantage that the download is under the control of the recipient. This can be better than having their email system tied up while a large attachment download takes place (although this is becoming less important as internet connections become faster). A single file sent this way by GoAruna can be up to 100mb. By registering with Aruna, you can also have 2gb of online storage. This can be used for backups and/or making files available to other people that may otherwise have needed to be sent as email attachments. Note: just as there are 1024kb in 1mb, there are 1024mb in 1gb.

There are other services similar to GoAruna. You may like to look at these:

http://www.yousendit.com
http://www.gigasize.com/index.php

© 2011-2017 David Leonard
Computer Support in London
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