Work with the example
Which date closes the report month containing February 10,2028? B5 is a numeric date. D5 uses EOMONTH(B5;0) after checking its type; D6 adds 1 to that month end. The result is a worksheet boundary, not a statutory deadline.
| Cell | Baseline date |
|---|---|
| B5 input | 2028-02-10 |
| D5 month end | 2028-02-29 |
| D6 next month | 2028-03-01 |
Edit the working cells
Display the real date cells as yyyy-mm-dd. Change B5 to 2027-02-10: the end becomes February 28 and the next start March 1. A fresh 2026-12-31 gives December 31 and 2027-01-01. Clear B5: both working results say Date missing rather than showing a plausible old serial date.
Check the failure case
E5’s B5+30 reaches March 11 at baseline, not February 29. A fixed day addition answers a different question and fails for month lengths and leap years.
What should the next-month result be for December 31,2026?
Show the worked answer
January 1,2027, as a numeric date.