WhenMathMulti-Date Offset Calculator
Apply the same calendar offset to a whole list of dates at once, such as shifting every milestone in a schedule by the same amount, and see exactly which results were constrained by month length.
Worked example
January 30 and January 31, 2027 both plus 1 month land on February 28: neither day exists in February, so both are constrained to its last valid day, even though they started on different days. The result table shows this for every date so the pattern is visible at a glance, not just the first one.
Limitations
This applies one offset to up to 50 dates using the constrain rule; it does not support a different rule per date or a per-date custom offset.
Frequently asked questions
- How many dates can I enter?
- Between 2 and 50, one per line, in YYYY-MM-DD format.