Calculate the number of whole days between two calendar dates. The difference uses millisecond timestamps divided by 24 hours, floored to an integer day count.
When to use it
- Project timelines and sprint lengths
- Rental or subscription period checks
- Teaching date arithmetic without spreadsheets
Limitations
Does not count business days or exclude holidays. End date must be on or after the start date. Invalid date strings return zero without a network lookup.
Example
From 2024-01-01 to 2024-01-11 yields 10 whole days—the end date is not counted as an extra day in this calculator.