The DAYS360 function calculates the number of days between two dates based on a 360-day year with twelve 30-day months. This function is commonly used in financial calculations where a simplified day count convention is used.


=DAYS360(Start_date, End_date, [Method])

Start_date The start date for calculating the number of days.
End_date The end date for calculating the number of days.
Method (Optional) An optional argument to specify the day counting method. Defaults to FALSE if omitted.

About DAYS360

When dealing with financial calculations that require a simplified approach to counting days between two dates, the DAYS360 function in Excel comes to the rescue. By assuming a 360-day year with twelve 30-day months, this function facilitates quick and straightforward day count calculations, often employed in various financial scenarios where simplicity is preferred over precise calendar days count. The DAYS360 function aligns with specific financial conventions that utilize a standardized method to determine interest accrual or payment periods without the need for intricate day-by-day calculations. Using this function streamlines the process of determining durations in financial agreements, investment periods, or interest calculations, especially in scenarios where a 30/360 day count methodology is utilized by default. The optional [Method] parameter caters to adjust the calculation to alternate day counting conventions if needed. This feature enhances the flexibility of the function to adapt to various financial practices without complicating the core functionality of date difference calculation.


Suppose you want to calculate the number of days between January 1, 2022, and March 15, 2022, using the default 30/360 day count convention. The DAYS360 formula would be: =DAYS360("01/01/2022", "03/15/2022") This will return the simplified count of days between the two dates.

Consider a scenario where you need to determine the duration between February 15, 2022, and June 30, 2022, utilizing the actual/actual day-count basis. The DAYS360 formula with this method specified would be: =DAYS360("02/15/2022", "06/30/2022", TRUE) This will provide the day count considering the actual number of days between the dates.


How does the DAYS360 function calculate the day count between two dates?

The DAYS360 function calculates the day count based on the following formula: Days = (360 * (End_year - Start_year)) + (30 * (End_month - Start_month)) + (End_day - Start_day)

Is the DAYS360 function suitable for calculating exact calendar days between dates?

No, the DAYS360 function is designed for simplified financial calculations based on a 360-day year with twelve 30-day months. It may not provide the precise count of calendar days between two dates due to its standardized day count methodology.

Can I customize the day-count method used by the DAYS360 function?

Yes, you can customize the day-count method by providing an alternate day counting convention through the optional Method argument. This allows adjusting the calculation to cater to specific financial requirements or different day-counting standards.

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