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Excel

COUPDAYS function in Excel

Returns the number of days in the coupon period that contains the settlement date

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

COUPDAYS syntax and parameters

Four arguments, three required.

  • settlementanyRequired

    The security's settlement date. The security settlement date is the date after the issue date when the security is traded to the buyer.

  • maturityanyRequired

    The security's maturity date. The maturity date is the date when the security expires.

  • frequencynumberRequired

    The number of coupon payments per year. For annual payments, frequency = 1; for semiannual, frequency = 2; for quarterly, frequency = 4.

  • basisanyOptional

    The type of day count basis to use.

COUPDAYS examples

Formulas you'll actually reuse.

  1. Days in the coupon period containing settlement — 180 on a 30/360 basis:

    =COUPDAYS(DATE(2026, 5, 15), DATE(2031, 3, 15), 2, 0)

    Result180

  2. The same on actual/actual (1) — the real count from Mar 15 to Sep 15:

    =COUPDAYS(DATE(2026, 5, 15), DATE(2031, 3, 15), 2, 1)

    Result184

COUPDAYS in Google Sheets

Same name — your formula ports as-is.

Try COUPDAYS in the playground

Edit the example — nothing to install.

Preloaded with the COUPDAYS formula from Example 1 — change anything and watch it respond.

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