All versions
Financial
The Excel COUPDAYBS function returns the number of days from the beginning of the coupon period to the settlement date. Settlement and maturity are dates wrap them in DATE() so Excel reads them correctly..
Quick answer:
=COUPDAYBS(DATE(2026,3,15), DATE(2031,1,1), 2) // a day/coupon count
Syntax
=COUPDAYBS(settlement, maturity, frequency, [basis])
| Argument | Description | |
|---|---|---|
settlement | Required | Settlement date. |
maturity | Required | Maturity date. |
frequency | Required | Coupons per year (1, 2, or 4). |
basis | Optional | Day-count basis. |
How to use it
COUPDAYBS returns the number of days from the beginning of the coupon period to the settlement date. Settlement and maturity are dates wrap them in DATE() so Excel reads them correctly..
=COUPDAYBS(DATE(2026,3,15), DATE(2031,1,1), 2) // a day/coupon count
Try it: interactive demo
Live demo
This is the formula pattern COUPDAYBS uses — copy it into Excel with your own numbers.
Result: computed in Excel
Practice workbook
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Frequently asked questions
How do I enter the dates?
Wrap settlement and maturity in DATE(year,month,day) so Excel reads real dates, not text.
Which Excel versions support it?
All modern versions.
Why might it return #NUM! or #VALUE!?
Out-of-range arguments (e.g. negative rate or settlement after maturity) give #NUM!; non-numeric inputs give #VALUE!.
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