A user defines mutually exclusive inbox and spam folders to which emails are routed based on a rating assigned to each email. A variable user-defined range defines a mapping of the ratings to each folder. Incoming emails are routing to one of the folders according to the range. A reference set of emails is designated, each having a rating and either an inbox label or a spam label. A display indicates the number the reference emails in each folder if the reference emails are routed to one of the folders according to their ratings and according to the user-defined range.