An unexpected value is returned when you use the DAYS360 function in Excel

Symptoms

When you use the DAYS360 function to calculate the number of days between two dates, an unexpected value is returned. For example, when you use the DAYS360 function with a start date of February 28 and with an end date of March 28, a value of 28 days is returned. You expect a value of 30 days to be returned for every full month.

Cause

This behavior may occur if you use the U.S. method, also known as the NASD method, with the DAYS360 function.

Note

By default, the U.S. method is used in the DAYS360 function. If you do not specify a method, the default method is used.

Workaround

To work around this behavior, use the European method with the DAYS360 function. To use the European method with the DAYS360 function, use the following syntax:

=DAYS360(cell number of start date,cell number of end date,TRUE)

More Information

Steps to reproduce the behavior

  1. In cell A1, type 2/28/2006, and then press ENTER.
  2. In cell A2, type 3/28/2006, and then press ENTER.
  3. In cell A3, type =DAYS360(A1,A2), and then press ENTER.

Results: A value of 28 is returned in cell A3.

References

For more information about the DAYS360 function in Microsoft Office Excel 2003, click Microsoft Excel Help on the Help menu, type DAYS360 in the Search for box in the Assistance pane, and then click Start searching to view the topic.

For more information about the DAYS360 function in Microsoft Excel 2002 or in Microsoft Excel 2000, click Microsoft Excel Help on the Help menu, type DAYS360 in the Office Assistant or the Answer Wizard, and then click Search to view the topic.

For more information about the DAYS360 function in Microsoft Excel 97, click the Index tab in Microsoft Excel Help, type DAYS360, and then double-click the selected text to view the "DAYS360 worksheet function" topic.