As of Excel 2007, Microsoft supports different weekend occurrences in the international version of the date functions (e.g. WORKDAY.INTL). The weekend conventions are defined by either a number or a 7-characters long string (code).

Weekend conventions specify which days of the week are weekends. The weekend convention is defined by a weekend number (1-7 and 11-17) or by a weekend string. Weekend string values are seven characters long and each character in the string represents a day of the week, starting with Monday. 1 represents a non-workday and 0 represents a workday. Only the characters 1 and 0 are permitted in the string. 1111111 is an invalid string, for example.

The weekend number (and weekends string) values indicate the following weekend days: