A method for obtaining a size of an Email of a terminal includes: the terminal extracting a preset standard mail template from a terminal file system, and using the standard mail template as a standard size of the Email; obtaining a size of contents input when a user edits the Email, and obtaining a size of a mail header and a size of a mail body of the Email according to the size of the contents input and the standard mail template; and adding the size of the mail header to the size of the mail body to obtain and display the size of the Email, so as to accurately obtain the size of the Email of the terminal. Accordingly, an apparatus for obtaining a size of an Email of a terminal is also provided by the invention.