Written By: Aryav Nagar Calculating the number of business days between varying lengths of time, even excluding federal holidays, may seem like a tricky problem to solve, but the solution is quite simple. While developing Stockscast , an AI-based stock market forecaster, I came across this issue as I needed to find the number of days the stock exchange would be open throughout the year. The solution I found involved the use of pandas.tseries.holiday.USFederalHolidayCalendar() and pandas.tseries.offsets.CustomBusinessDay() functions are found in the Pandas library. By creating a custom calendar, using the CustomBusinessDay function, with the frequency of USFederalHolidayCalendar , we can create a calendar excluding both weekends and federal holidays. Next, find the length of time you want to calculate the number of business days in. In my case, I needed to find the number of business days between one week, one month, three months, six months, and one year from now. Finally, w