COUPNUM in Collabora Office: Count Remaining Regular Coupon Payments
Count remaining Collabora coupon payments with COUPNUM, audit explicit schedules, and distinguish payment counts from fractional years and cash amounts.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
Quick answer: =COUPNUM(DATE(2001;1;25);DATE(2001;11;15);2;3) has documented result 2. It counts remaining interest payments between settlement and maturity, rather than measuring elapsed years.
Syntax and required inputs
=COUPNUM(Settlement; Maturity; Frequency [; Basis])
Settlement is the purchase/settlement date. Maturity is the expiry date. Frequency is the required number of annual payments. Basis is optional and defaults to zero.
| Basis | Documented day-count convention |
|---|---|
| 0 or omitted | US NASD, twelve 30-day months |
| 1 | Actual days in months and actual days in the year |
| 2 | Actual days in months, 360-day year |
| 3 | Actual days in months, 365-day year |
| 4 | European method, twelve 30-day months |
Use explicit date values, preferably DATE formulas, rather than ambiguous date-looking text. Frequency is a number of payments per year, not a number of months: 1, 2, and 4 mean annual, semiannual, and quarterly payments. Monthly frequency 12 is outside the stated contract.
The function has no coupon-rate, principal, price, or yield input, so its output is a count. There is also no issue-date or special first/last coupon input; the examples here use regular schedules and avoid settlement exactly on a coupon boundary.
Example: count the vendor’s two payments explicitly
Enter =DATE(2001;1;25) in A2, =DATE(2001;11;15) in B2, 2 in C2, and 3 in D2. In E2 enter:
=COUPNUM(A2;B2;C2;D2)
The documented expected result is 2. The regular semiannual remaining payment dates are 2001-05-15 and 2001-11-15. The final maturity-date coupon is included in this documented example.
There are fewer than twelve months from settlement to maturity, but two payment dates still remain. A formula that simply takes a year fraction and multiplies by two need not return this integer count.
Keep E2 formatted as an ordinary number. Formatting a coupon count as a date or percentage makes the result harder to interpret.
Example: compare three regular frequencies
Use settlement 2026-10-17 and maturity 2028-01-15, with basis three. Independently enumerating regular schedules gives:
| Frequency | Remaining dates | Expected count |
|---|---|---|
| 1 | 2027-01-15; 2028-01-15 | 2 |
| 2 | 2027-01-15; 2027-07-15; 2028-01-15 | 3 |
| 4 | 2027-01-15; 2027-04-15; 2027-07-15; 2027-10-15; 2028-01-15 | 5 |
Put 1, 2, and 4 in C5:C7 with the same date inputs in the other columns, then use =COUPNUM(A5;B5;C5;D5) and fill down. These are independent regular-schedule expectations, not native Collabora observations.
The quarterly count is five because the October 15, 2026 coupon has already occurred. It is not simply four times a rounded number of remaining years.
Advanced application: estimate undiscounted regular coupon cash
Suppose a hypothetical security has principal 1000, annual coupon rate 6%, and semiannual payments. A regular coupon amount is independently 1000×0.06/2=30.
For the newer semiannual schedule’s count of 3, the sum of the three assumed regular coupon amounts is 90. A transparent worksheet formula is =1000*6%/2*E6 if E6 contains that coupon count.
This is an undiscounted coupon total under stated assumptions. It excludes principal repayment, price, accrued interest, taxes, reinvestment, discounting, and any irregular coupon amounts. It is not the security’s market value or return.
If principal 1000 is repaid separately at maturity, adding it gives a modeled undiscounted cash total of 1090. Preserve the coupon and redemption components separately so the calculation does not mislabel them.
Advanced audit: compare count with an explicit date list
Place the three semiannual dates in H2:H4 as DATE formulas. COUNT should count 3 numeric dates in that fixed list. Compare that number with the COUPNUM result, while also confirming that each date falls after the chosen settlement and no later than maturity.
A matching count does not prove all dates are correct. Two wrong schedules can contain the same number of entries. Use MIN and MAX as simple boundary checks, retaining date formatting on those results.
Errors and limitations
Check date order, valid numeric dates, permitted frequency, and the intended basis. The dedicated Collabora section does not enumerate a complete native error table, fractional-input handling, every month-end rule, or settlement-on-coupon equality behavior.
A security with an odd first or last coupon may not fit the regular schedule represented by these inputs. COUPNUM cannot infer special dates that were never supplied. The documented two-payment control and explicit regular-date enumerations define this guide’s verification scope.
Availability and verification
The exact function is documented in Collabora Office 26.04 desktop help, retrieved and reviewed on October 17, 2026. This establishes a documentation scope, not the first release that introduced the function or the last version in which it works; those versions and any retirement date remain unestablished. Collabora Online and mobile support are not inferred from desktop help, nor is behavior in another spreadsheet product.
The examples are documentation-based expectations with independent calculations. They have not been executed in Collabora Office. No application screenshot or native error/coercion certification is implied. Formulas use English function names and semicolon argument separators.
References
- Collabora Office 26.04: COUPNUM (checked October 17, 2026).
- Editorial testing standards.