You can use the following expression to take a date field value as input and return the day of the week: // define an array of the days of the week to use as a lookup structure var daysOfWeek = ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday']; // This converts a date field in the record to a JavaScript date object var d = DATEVALUE($the_date_field); // If you wanted to use today’s date or any other specific date … // var d = new Date(); // var d = new Date('4/15/1984'); SETRESULT(daysOfWeek[d.getDay()]);