Month to date includes an important caveat when used in business. Here, month to date refers to the first of the month to the last business day before the given current date. For instance, if today were Aug. 21, the month-to-date would equal Aug. 1 to Aug. 20. This is because business has not been finalized for the current day. Month to date is used for similar metrics as the year to date, such as measuring earnings, return, and income.