In this article
COUPDAYBS counts days from the last coupon date to the settlement date: the accrued-interest days. Used for bond pricing and accrued interest on half-yearly coupons.
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Syntax
=COUPDAYBS(settlement, maturity, frequency, [basis])| Argument | What it means |
|---|---|
settlement |
Purchase date |
maturity |
Maturity date |
frequency |
1, 2 or 4 coupons a year |
basis |
Day count |
Examples
Example 1
=COUPDAYBS(A2,B2,2,1)Result: 5. See the worked example table below for more cases.
COUPDAYBS in practice
Where you will use it
- Accrued interest when buying a bond between coupons
- Cash-flow schedules
- Treasury desk reports
Worked example
| Settlement | Maturity | Formula | Result |
|---|---|---|---|
| 05-10-2026 | 31-03-2031 | =COUPDAYBS(A2,B2,2,1) | 5 |
| 10-01-2026 | 31-12-2030 | =COUPDAYBS(A3,B3,2,1) | 10 |
| 15-06-2026 | 15-06-2028 | =COUPDAYBS(A4,B4,2,1) | 0 |
Results calculated in Excel.
Mistakes people make
| Mistake | What to do instead |
|---|---|
| Settlement after maturity | #NUM! |
| Wrong frequency | Use the bond's real coupon frequency |
Related functions
📚 Part of the free Excel course: Beginner → Expert · Try it in the Formula Lab or ask the AI Helper.
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