The hosting account has a master disk quota which is the amount of space that all web pages, databases, file storage, and email boxes use. This disk quota is determined by your hosting account package. (This can be upgraded if necessary. See our hosting services page for more details.) Each email account can optionally have its own individual quota, which sets the maximum amount of space usable for that particular email address. This includes messages (and attachments) stored on the server in the inbox, sent items, trash, etc. At the time of email account creation, the email quota can be set (or modified at any time thereafter). Note that email message file attachments can take up 5-10M per attachment, especially if it's a video or large graphic file. If an email box is over quota, a sender to that address will receive a rejection error message similar to this: mailbox is full: retry timeout exceeded