Microsoft Excel does not have a specific function to calculate weeks between days. However, you can calculate this value by using the "INT" function and then dividing the result by seven. The "INT" function rounds whatever number you have. So, if you find the number of days between two dates and then divide by seven, the result is a number that is a decimal. By using the "INT" function, Excel rounds this amount to determine exactly how many weeks you have.
Type your first date in cell A1.
Type your second date in cell A2.
Type "=INT((A2-A1)/7)" in cell A3 to calculate the number of weeks.