Determine which month you would like to calculate the number of weeks for.
Enter the number of days in the particular month you have chosen into a calculator.
Divide that number by seven (the number of days in a week) by pressing the division button, the number and the "=" or "Enter" button. The result will determine the precise number of weeks in that given month. For example, if you chose March 2011, you would make the following calculation: 31 days/7 days = 4.43 weeks.
Open your calendar to the desired month.
Count the number of complete weeks in that particular month. A complete week equals seven days.
Divide the remaining days by seven (the number of days in a week) and you will find the total number of weeks in your chose month. For example, if you chose April 2011, you will note on your calendar that April has four complete weeks with two remaining days. If you divide two by seven you get 0.29. Add the two together and you come up with 4.29 weeks in April.