COUPDAYSNC Function in Google Sheets: Formula, Examples & Troubleshooting

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

Google documents bases 0 US NASD 30/360, 1 Actual/Actual, 2 Actual/360, 3 Actual/365, and 4 European 30/360. Its guidance recommends DATE or another date conversion rather than text. Google COUPDAYSNC reference.

The function returns a count, not the next coupon’s date. It also differs from COUPDAYS, which describes the full coupon period containing settlement. Similar names do not make those outputs interchangeable.

Assume a hypothetical security pays January 15 and July 15, with a final coupon on January 15, 2028. Create these inputs:

1. Enter =COUPDAYSNC(B2,B3,B4,B5) in B7.
2. Format B7 as a number.
3. Compare its expected value of 122 with an independent calendar check: =DATE(2026,7,15)-B2.
4. Keep the next scheduled date, July 15, visible in a separate labeled cell if the worksheet is used for planning.

The actual interval from January 15 to July 15, 2026 is 181 days. Settlement is 59 days after January 15, leaving 122. This is a calendar explanation for the stated regular schedule; it does not establish an arbitrary irregular-coupon algorithm.

A basis-0 comparison is:

=COUPDAYSNC(B2,B3,B4,0)

For the non-month-end March-15 to July-15 interval, the expected US 30/360 count is 120. The two counts differ because one measures actual calendar days and the other follows a financial convention. Use the basis required by your model rather than picking whichever result looks familiar.

Keep maturity, frequency, and basis 1 fixed. Enter these three settlement dates in D2:D4 with DATE formulas:

In E2 use =COUPDAYSNC(D2,$B$3,$B$4,$B$5) and fill through E4. In F2 use =IF(E2<=45,"Within 45 days","Later") and fill down. Expected labels are Later, Within 45 days, and Later.

The jump from a short countdown to a longer one after July 15 is expected for a repeating schedule. It does not indicate that time ran backward. This example deliberately skips settlement on July 15 itself because the retrieved source does not establish that equality boundary.

The IF threshold is an illustrative review rule. It neither schedules an alert nor checks whether an issuer has actually paid. Google’s IF documentation establishes the branch order used by the formula.

If you need a literal calendar countdown, an actual-day model is appropriate for the illustrated date subtraction. A 30/360 count is not a count of business days or actual calendar dates. COUPDAYSNC has no holiday-list or weekend parameter.

For an independently modeled 30-unit semiannual coupon in the original Actual/Actual example, the remaining fraction would be 122/181; multiplying by 30 gives approximately 20.220994. That is only a transparent fraction of a specified coupon. COUPDAYSNC itself does not compute income, accrued interest, present value, or entitlement to a payment.

The result looks like a date: set the output display to number. A day count and a date serial can look similar when formatted incorrectly.

You expected the full 181 days: check whether you need the entire coupon period or only the interval after settlement.

A default changed the comparison: an omitted basis is 0. All examples here specify the basis explicitly to make the model reviewable.

Invalid frequency: the documented options are 1, 2, and 4 payments per year. Do not supply months between payments.

Special schedules or invalid inputs: exact month-end treatment, coupon-date equality, fractional-date handling, and native error labels were not established from the reviewed text. Verify those separately. The signature does not include a custom coupon calendar or irregular first-coupon date.

Google currently documents COUPDAYSNC. Its introduction, retirement, and last working version are unknown from this evidence. No cross-product equivalence is assumed.

Reviewed October 17, 2026: Google COUPDAYSNC, DATE, and IF.

Related published guides: DATE, DAYS360, and IF.