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COUPDAYS function in Google Sheets

Calculates the number of days in the coupon, or interest payment, period that contains the specified settlement date.

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

COUPDAYS syntax and parameters

Four arguments, three required.

  • settlementanyRequired

    The settlement date of the security, the date after issuance when the security is delivered to the buyer.

  • maturityanyRequired

    The maturity or end date of the security, when it can be redeemed at face or par value.

  • frequencynumberRequired

    The number of interest or coupon payments per year (1, 2, or 4).

  • day_count_conventionnumberOptional

    [ OPTIONAL - 0 by default ] - An indicator of what day count method to use. 0 indicates US (NASD) 30/360 - This assumes 30 day months and 360 day years as per the National Association of Securities Dealers standard, and performs specific adjustments to entered dates which fall at the end of months. 1 indicates Actual/Actual - This calculates based upon the actual number of days between the specified dates, and the actual number of days in the intervening years. Used for US Treasury Bonds and Bills, but also the most relevant for non-financial use. 2 indicates Actual/360 - This calculates based on the actual number of days between the specified dates, but assumes a 360 day year. 3 indicates Actual/365 - This calculates based on the actual number of days between the specified dates, but assumes a 365 day year. 4 indicates European 30/360 - Similar to 0, this calculates based on a 30 day month and 360 day year, but adjusts end-of-month dates according to European financial conventions.

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 Excel

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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