COUPDAYS

How many days the coupon period around the settlement date lasts.

Group: Financial. Compatible with DAX.

Syntax

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

Parameter	Type	Description
`settlement`	Date	The day the buyer takes the security over; later than its issue.
`maturity`	Date	The day the security ends and its face value is repaid.
`frequency`	Whole number	Coupons a year: 1 for yearly, 2 for half-yearly, 4 for quarterly.
`basis`	Whole number optional	The day count, by number: US 30/360 (0, when left out), actual/actual (1), actual/360 (2), actual/365 (3) or European 30/360 (4).

Returns

Number. The length in days of the coupon period that holds settlement.

Remarks

On the 30/360 bases (0 and 4) and on actual/360 a period is 360 / frequency days, on actual/365 it is 365 / frequency (182.5 for half-yearly coupons), and on actual/actual it is the period's actual days.
For a bond that matures on a month's last day, the actual/actual length can be a few days off the gap between COUPPCD and COUPNCD: Power BI counts that period on its own schedule, and OpenBI gives the same answer.
Coupons fall on maturity's day of the month, stepping back from maturity by 12 / frequency months. When maturity is the last day of a month, every coupon date is a month's last day too.
A settlement on or after maturity is an error. The dates are taken as whole days. frequency and basis are rounded to whole numbers first; a frequency other than 1, 2 or 4, or a basis outside 0 to 4, is an error.

Examples

One period, five day counts

EVALUATE
ROW (
    "Basis 0", COUPDAYS ( DATE ( 2011, 1, 25 ), DATE ( 2011, 11, 15 ), 2, 0 ),
    "Basis 1", COUPDAYS ( DATE ( 2011, 1, 25 ), DATE ( 2011, 11, 15 ), 2, 1 ),
    "Basis 2", COUPDAYS ( DATE ( 2011, 1, 25 ), DATE ( 2011, 11, 15 ), 2, 2 ),
    "Basis 3", COUPDAYS ( DATE ( 2011, 1, 25 ), DATE ( 2011, 11, 15 ), 2, 3 ),
    "Basis 4", COUPDAYS ( DATE ( 2011, 1, 25 ), DATE ( 2011, 11, 15 ), 2, 4 )
)

Basis 0	Basis 1	Basis 2	Basis 3	Basis 4
180	181	180	182.5	180

COUPDAYBS, COUPDAYSNC, COUPNCD, COUPPCD.

Last updated 3 November 2026 · OpenBI Studio 0.3.74