The Excel COUPDAYS Function

Related Functions:

Function Description

The Excel Coupdays function calculates the number of days in a coupon period that contains the settlement date.

The syntax of the function is:

COUPDAYS( settlement, maturity, frequency, [basis] )

Where the arguments are as follows:

settlement-The settlement date of the security.
maturity-The maturity date of the security.

An integer, representing the number of coupon payments per year. This must have the value 1, 2, or 4, meaning:


An optional integer argument that specifies the day count basis to be used.

This must be one of the following values:

BasisDay Count Basis
0 (or omitted)US (NASD) 30/360
4European 30/360
The financial day count basis rules are explained on the Wikipedia Day Count Convention page

Note that the settlement and maturity dates should be input as either:


Warning: If you attempt to input these dates as text, there is a chance that Excel may misinterpret them due to different date systems, or date interpretation settings on your computer.

Excel Coupdays Function Example

Cell A3 of the spreadsheet below shows the Excel Coupdays function, used to calculate the number of days in the period containing the settlement date, for a security that has the settlement date 01-Jan-2011, maturity date 25-Oct-2012, and 4 payments per year. The US (NASD) 30/360 day count basis is used.

3=COUPDAYS( A1, A2, 4 )

Note that, in the above example:

Further details and examples of the Excel Coupdays function are provided on the Microsoft Office website.

Coupdays Function Errors

If you get an error from the Excel Coupdays Function, this is likely to be one of the following:

Common Errors

Occurs if either:

  • The supplied settlement date is ≥ maturity date;
  • The supplied frequency argument is a number that is not equal to 1, 2 or 4;
  • The supplied [basis] argument is a number that is not equal to 0, 1, 2, 3 or 4.

Occurs if either:

  • The supplied settlement or the supplied maturity dates are not a valid Excel dates;
  • Any of the supplied arguments are non-numeric.