Guide to Excel's Volatile NOW Function For The Data and Time

Add the current date and time with Excel's NOW function

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One of Microsoft Excel's best-known date functions is the NOW function. The NOW function adds the current date or time to a worksheet. It can also be used in date and time formulas to find the number of day past the current date, the number of days to the end of the month, and the current minute.

The information in this article applies to Excel versions 2019, 2016, 2013, 2010, and 2007.

NOW Function Syntax and Arguments

A function's syntax refers to the layout of the function and includes the function's name, brackets, comma separators, and arguments. The syntax for the NOW function is:

The NOW function has no arguments. The data is entered inside the function's parentheses. 

Enter the NOW Function

Like most Excel functions, the NOW function is entered into a worksheet using the function's dialog box. Because it takes no arguments, the function can be entered into the active cell by typing =Now() and pressing Enter. The result displays the current date and time.

Screen shot of Excel showing uses of the NOW() function

To change the information displayed, adjust the cell's formatting to show just the date or the time using the Format tab.

Shortcut Keys to Formatting Date and Time

To quickly format the NOW function output, use the following keyboard shortcuts:

Date (day-month-year format):


Time (hour:minute:second and AM/PM format):


Serial Number/Date

The reason the NOW function takes no arguments is that the function obtains its data by reading the computer's system clock. Windows versions of Excel store the date as a number representing the number of full days since midnight January 1, 1900, plus the number of hours, minutes and seconds for the current day. This number is called a serial number or serial date.

Volatile Functions

Since the serial number continually increases with each passing second, entering the current date or time with the NOW function means the function's output continually changes.

Close-Up Of Clock
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The NOW function is a member of Excel's group of volatile functions, which recalculate or update every time the worksheet in which they are located recalculates — just as SUM and OFFSET used together do the same.

For example, worksheets recalculate each time they are opened or when certain events occur, such as the entering or changing of data in the worksheet, so the date or time changes unless automatic recalculation is turned off.

Forcing Worksheet/Workbook Recalculation

To force the function to update at any time, press one of the following key combinations:

  • Shift+F9 to recalculate the active or current worksheet.
  • F9 to recalculate all open workbooks.

Keeping Dates and Times Static

Having the date and time continually change is not always desirable, especially if they are used in date calculations or if you want a date or timestamp for a worksheet.

Screen shot of Excel showing how to format for date or time

Options for entering the date or time so they do not change include shutting off automatic recalculation, typing dates and times in manually, or entering them using the following keyboard shortcuts:

The time shortcut is: