Question: how to calculate date from week number?
Answer: How to get the date from a week number. To get the date of the Monday in a week, use =DATE( A1 , 1, -3 + 7 * B1 - WEEKDAY(DATE( A1 , 1, 4), 2) + 1) . Cell A1 contains the four-digit year (e.g. 2013), and cell B2 contains the week number (1-53).