How the difference is calculated
The total is the number of whole days between the two dates, on the Gregorian calendar. The same span is also shown in weeks + days, and as a calendar breakdown of years, months, and days.
More detail
Why the calendar breakdown differs from total ÷ 30
Months don't all have the same number of days, so “1 year 2 months 10 days” isn't the same as dividing total days by 30. The breakdown counts whole calendar years and months first, then whatever days are left over — the same way you'd count on a calendar.
Tip. Leave the start date at today to count down (or up) to any future or past date — useful for deadlines, trip planning, or figuring out how long ago something happened.
Frequently asked questions
How many days are there between two dates?
Enter a start and end date — the Total days output gives the whole number of days between them on the Gregorian calendar, e.g. Jan 1 to Dec 31, 2026 is 364 days.
Why is the calendar breakdown not the same as total days ÷ 30?
The calendar breakdown counts whole calendar years and months first, then the leftover days. Since months have 28–31 days, this differs from a flat division by 30.
What if the end date is before the start date?
The result is an absolute (unsigned) difference, so it doesn't matter which date you enter first — the total days and breakdown come out the same either way.
How do I see the span in weeks instead of just days?
The In weeks output automatically converts the total days into whole weeks plus leftover days, e.g. 100 days shows as 14 wks 2 days.