As a result, using the WEEKDAY function to calculate days of the week for dates in 1900 before March 1 yields incorrect results in Microsoft Excel worksheets built using the 1900 date system.

Excel’s Date & Time functions ease the workload for bookkeepers, project planners, HR departments, and other jobs where time is money. The four functions covered here—ISOWEEKNUM, WEEKNUM ...

Excel has over 475 formulas in its Functions Library, but we've selected the most popular, from date and time functions to mathematics and simple data manipulation.

Mary Ann Richardson explains that when concatenating date and text cell data in an Excel formula, you need to convert date cells to text to avoid unexpected results.

Formulas are powerful tools for performing calculations and analyzing data in Excel. In this beginner’s guide, you’ll learn how to use formulas and explore some popular built-in functions.

We show you how to use Excel to count days between two dates using the DAYS, DATEDIF, NETWORKDAYS, and TODAY functions, and Subtraction.