# The Excel COUPDAYS Function

Related Functions:
COUPDAYBS
COUPDAYSNC

## 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.
frequency -

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

 1 - Annually 2 - Semi-Annually 4 - Quarterly
[basis] -

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

This must be one of the following values:

Basis Day Count Basis
0 (or omitted) US (NASD) 30/360
1 actual/actual
2 actual/360
3 actual/365
4 European 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:

• References to cells containing dates
or
• Dates returned from formulas.

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.

Formulas:
A
1 01-Jan-2011
2 25-Oct-2012
3 =COUPDAYS( A1, A2, 4 )
Results:
A
1 01-Jan-2011
2 25-Oct-2012
3 90

Note that, in the above example:

• As recommended, the settlement and maturity dates have been supplied to the function as references to cells containing dates;
• The [basis] argument has been omitted from the function. Therefore, the function uses the default value 0 (denoting the US (NADS) 30/360 day count basis).

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
 #NUM! - 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. #VALUE! - 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.