Excel DAYS function


The Excel DAYS function calculates the number of days between two dates. It is a straightforward yet powerful tool for date arithmetic, allowing users to determine the duration between two points in time, which is essential for project planning, tracking time-sensitive activities, or analyzing time-series data.
					=DAYS(end_date, start_date)
  • end_date: The end date of the period
  • start_date: The start date of the period
Return value
The number of days between the two dates as an integer. The value can be positive or negative, depending on the order of the dates.

How to use

Simply input the end date and the start date into the function. The end date and start date can be entered as date strings in quotes (e.g., “2023-01-01”), as serial numbers representing dates, or as references to cells containing dates. The DAYS function will then calculate the difference between these two dates, returning the total number of days separating them.


Simple DAYS
Counting Days Between Dates: To find out how many days are between January 1, 2023, and March 1, 2023.
					=DAYS("2023-03-01", "2023-01-01")

This formula returns 59, indicating there are 59 days between January 1, 2023, and March 1, 2023.
DAYS for Project Deadlines
Calculating Days Until a Deadline: Determining the number of days remaining until a project’s deadline on December 31, 2023, from today’s date.
					=DAYS("2023-12-31", TODAY())

Assuming today is October 1, 2023, this formula calculates the days remaining until the year’s end, aiding in project timeline management.
DAYS for Age Calculation
Determining Age in Days: Calculating how many days old someone is as of today, given their birthdate on April 15, 1990.
					=DAYS(TODAY(), "1990-04-15")

This example shows how to use DAYS to calculate the age in days from a birthdate to the current date.
DAYS with Cell References
Using Cell References for Date Differences: Calculating the difference in days between two dates listed in cells A1 (start date) and B1 (end date).
					=DAYS(B1, A1)

If A1 is “2023-06-01” and B1 is “2023-06-15”, the formula returns 14, demonstrating the use of DAYS with cell references to calculate the period between two dates.

Additional Notes

  • The DAYS function is part of Excel’s rich set of date and time functions, simplifying calculations involving periods.
  • Ensure dates are entered in a format recognized by Excel to avoid errors or unexpected results.

Related Functions

Excel DAYS360 function

The Excel DAYS360 function calculates days between dates using a 360-day year, ideal for financial and accounting calculations.


The Excel NETWORKDAYS.INTL function calculates workdays between dates with custom weekends, ideal for international scheduling.

Excel NETWORKDAYS function

The Excel NETWORKDAYS function calculates working days between two dates, excluding weekends, useful for project timelines.

Excel YEARFRAC function

The Excel YEARFRAC function calculates the fraction of the year between two dates, essential for financial calculations.

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