Understanding Email Restrictions

An overview of storage space, bandwidth, and other limitations and restrictions imposed on email accounts.

Storage Space

"Storage space" is a measure of how much disk space your email occupies on your email provider's servers. It is usually measured in MB or "megabytes". A MB is a million bytes of information - typically, one byte can represent one letter or number. Another measurement you may see used is the KB or "kilobyte" - which is a thousand bytes.

A small text only email might occupy just a few KB of storage space whereas a large email with attachments, such as a video or MP3 file, might take up several MB.

Because the type of email and the size of attachments can vary so much, it's hard to predict an "average" amount of space that you'll need for storing your emails. However, if you mainly send and receive text emails, you could probably store around 200 messages per MB of storage space. If you send a lot of attachments and files, you should count on being able to store 1-2 messages per MB or less.

Most email providers offer between 5MB and 100MB of storage space, which is ample for normal use but which can quickly get used up if you receive large files. Some providers will let their users pay to upgrade their storage space, leaving much more room for messages in a user's mailbox.

Bandwidth

"Bandwidth" tells you how much data you can send/receive in a month. A bandwidth allocation of 25MB, for example, means that you can send and receive a total of 25 megabytes of email in a month.

Bandwidth and storage space go together - bandwidth tells you how much email you can send/receive and storage space tells you how much email you can keep in your mailbox.

You need to choose an email service which gives you a good balance between bandwidth and storage space. It's no good having 500MB of bandwidth to play with if your mailbox can only hold 2MB - you'd have to completely empty your mailbox 50x in a month to take full advantage of it! Similarly, it's not very useful having 100MB of storage space but only 20MB of bandwidth - that means it would take 5 months to completely fill your mailbox!

Bandwidth is used up every time an email message "moves", so for example when a message arrives at your email mailbox on the provider's server it uses up bandwidth. If you log into a webmail interface to read the message, the mail stays on the server - but if you download it to your own PC using POP3/IMAP, then the message has "moved" again and you've used up the bandwidth used up in transmitting the message a second time. A similar scenario applies to email that you're sending - if it has to move from your computer to the provider's server, then from the provider's server onto the Internet, that's 2 lots of bandwidth used up.

Bandwidth is also used up for every email recipient. If you send a 1MB message to 20 people, it will use up 20MB of bandwidth. This is why it's possible to use up a bandwidth allocation very, very quickly if you're accustomed to sending emails to a whole group of friends or colleagues each time.

WARNING! BEWARE OF PROVIDERS OFFERING "UNLIMITED" BANDWIDTH
It's impossible for email providers, especially free services, to offer truly unlimited bandwidth. Simple economics prevent them doing so, as typically an email service might itself have to pay US$1 per 1000MB of bandwidth to its hosting provider. If users really had access to "unlimited" bandwidth then potentially a single free user might cost them hundreds of dollars a month!

Email providers will protect themselves by burying the real restrictions on bandwidth in their Terms and Conditions, either explicitly by defining "unlimited" as a specific amount of data, or implicitly using weasel words such as "No user shall consume more than their fair share of system resources."

Inactivity Limits

Most email providers (especially free ones) will set a certain "inactivity limit" on accounts. This is a time period that defines the maximum allowable time between logins. For instance, a provider with an inactivity limit of 30 days requires users to log into their accounts at least once every 30 days to keep those accounts active.

The way inactive accounts are handled varies from provider to provider, but inactive accounts may be locked against receiving new main or deleted.

If you think you're going to be away for a very long time and unable to access your email, it's worth contacting the Support team for your email service to let them know - they may be able to set up your account so that it is not subject to the standard inactivity limit, meaning that it will stay available to you until you return. Either that or consider upgrading to a paid service level - generally paid accounts are kept open until the payments stop, rather than until some artificial time limit since last login is reached.

Email Size Limits

Most email providers set a maximum size on the amount of information (data) you can send or receive in a single email message. This may be MUCH less than the size of your email storage space. This size limit will dictate the maximum size of any attachments you want to send or receive, since you won't be able to transmit files that are larger than the email size limit.

For instance, if a provider limits emails to 5MB or less, you won't be able to use the service to send a 6MB file (and you'd have to send two 3MB files as two separate messages).

It's important to remember that different email providers have very different limits on the size of email their users can send or receive, so that even if your email service is able to send e.g. a 30MB message, your correspondent at a different email service might not be able to receive it.

If you're lucky you'll receive a "bounce" or "error" message if you try and send someone an email that is larger than their email service will allow, but unfortunately it really is a matter of luck as there is no guaranteed standard Internet-wide way for email services to respond to messages that are too big. Because of this, if you're sending somebody some important files, it's a good idea to send them a separate, short email to check with them that they have received all the information you sent them.

Outgoing Message Restrictions

Many email providers place restrictions on the number of outgoing email messages you can send in a certain time period, such as an hour, a day or even a month. They do this primarily to minimize the chance that their email service will be used to send out spam (unsolicited bulk commercial email) but the limits can sometimes catch you unawares.

Outgoing limits are generally based on the total number of recipients for the messages you're sending, so for example 100 messages sent to 1 person each, or 10 messages sent to 10 people each would both use up "100 messages" worth of outgoing email.

You need to choose an email service which gives you a good balance between bandwidth and storage space. It's no good having 500MB of bandwidth to play with if your mailbox can only hold 2MB - you'd have to completely empty your mailbox 50x in a month to take full advantage of it! Similarly, it's not very useful having 100MB of storage space but only 20MB of bandwidth - that means it would take 5 months to completely fill your mailbox!

Incoming Message Restrictions

Although less common than outgoing message restrictions, some providers limit the number of incoming emails they will accept for users in a given period of time e.g. an hour or a day. They do this to prevent abuse.

If you participate in email discussion lists where there are hundreds or thousands of posts per day, you may want to explore the option of setting your subscription to "digest mode" (if available) to cut down on the number of incoming messages you receive and so avoid tripping any incoming message restrictions.

NOTE: The Yahoo! Groups service is notorious for hosting some groups that generate thousands of posts a day - some providers have therefore chosen to block incoming Yahoo! Group messages entirely rather than risk having their user's accounts bombarded with messages.

 

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