# The Excel COUPDAYBS Function

Related Functions:
COUPDAYS
COUPDAYSNC

## Function Description

The Excel Coupdaybs function calculates the number of days from the beginning of a coupon's period to the settlement date.

The syntax of the function is:

COUPDAYBS( 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:

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

• 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 Coupdaybs Function Example

Cell A3 of the spreadsheet below contains an example of the Excel Coupdaybs function, used to calculate the number of days from the beginning of a coupon's period to the settlement date. The security has the settlement date 01-Jan-2011, the maturity date 25-Oct-2012, and 4 payments per year. The US (NASD) 30/360 day count basis is used.

Formulas:
A
101-Jan-2011
225-Oct-2012
3=COUPDAYBS( A1, A2, 4 )
Results:
A
101-Jan-2011
225-Oct-2012
366

Note that, in the above example:

• As recommended, the date arguments have been input as references to cells containing dates;
• As the [basis] argument has been omitted, the function uses the default value 0 (denoting the US (NADS) 30/360 day count basis).

For further details and examples of the Excel Coupdaybs function, see the Microsoft Office website.

## Coupdaybs Function Errors

If you get an error from the Excel Coupdaybs 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.