Many times you may need to calculate the number of work days between two dates. For example, you may want to know how many days you have worked in specific period if you are eligible to take a vacation day after a certain number of work days have elapsed. You can calculate this manually, but it can become tedious, especially if the dates are far apart. Microsoft Excel has a function that can perform this calculation for you in no time. Alternatively, there are also online calculators available that will calculate the number of working days for you by simply entering a few inputs. Learn how to calculate work days between two dates using all three methods.

Calculate the number of work days between two days manually by starting with the number of days in each month from the start date to the end date. Add the total number of days. Count the number of Saturdays and Sundays in the period and subtract this amount from the number of days. Then subtract the number of holidays.

For example, if we want to know how many work days there were in January 2009 and February 2009, we would begin with 59 (31+28) and subtract 17. Exclude all of the holidays: Jan.1, Jan. 19, and Feb. 16. There were 39 work days between Jan. 1, 2009, and Feb. 28, 2009.

Use the NETWORKDAYS function in Microsoft Excel. The function takes three arguments: start date, end date, and holidays. List all of the holidays in a column and use the range for the holiday argument. In our example, the formula would appear as "=NETWORKDAYS(A1,A2,B1:B3)" if the start date were in A1, end date in A2, and the holiday dates in column B. The function returns 39.

Use an online calculator that will perform the calculation for you. Visit the calculator at Publish or Persish Software Press, then select the start date and end date. The boxes in red indicate a holiday. Count the number of holidays and enter it in the Holidays field. Hit "Enter" to see the number of work days.