Count the calendar days between two dates without assuming that every month has the same length. Enter a start date and an end date to see the elapsed day count, whole weeks with remaining days, and date-based hours. By default, the start date is excluded. Select Count both dates for an inclusive calendar count. You can enter the dates in either order; the tool reports the size of the gap and explains the direction. This is a calendar-day tool, so it does not remove weekends or holidays.
Worked example
| Start | End | Elapsed days | Inclusive days |
|---|---|---|---|
| 02/28/2024 | 03/01/2024 | 2 | 3 |
| 02/28/2025 | 03/01/2025 | 1 | 2 |
How it works
Each date is converted to a continuous Julian day number using the U.S. Naval Observatory conversion algorithm. Subtracting the day numbers gives a signed interval. Taking its absolute value gives the gap shown by this tool. Inclusive counting adds the starting date to that gap. Leap days are included according to the Gregorian leap-year rule.
Elapsed days = abs(Julian day number(end) - Julian day number(start))
Inclusive days = elapsed days + 1
Whole weeks = floor(days / 7); remaining days = days % 7
Elapsed and inclusive counts
Elapsed days measures how many calendar-date boundaries separate the two inputs. If the dates are the same, no date boundary has been crossed, so the elapsed result is zero. Inclusive counting instead asks how many calendar dates lie in the range when both endpoints belong to it. The same-date inclusive result therefore counts that one calendar date.
Choose the option that matches the wording of your task. A date gap is usually an elapsed interval. A list of dates to include in a calendar range may need the inclusive option. The calculator offers both, but it cannot decide how an outside policy defines its deadlines. Check the policy if a result will be used for a filing, booking or other formal cutoff.
Weeks, hours and reversed dates
The weeks field divides the selected day count into complete seven-day groups and leftover days. It does not align the groups with a particular weekday or calendar-week numbering system. Hours multiply the selected day count by twenty-four, following the fixed-day conversion described by NIST. No clock times are entered, so daylight saving changes and partial days are outside this calculation.
Reversing the start and end dates leaves the size of the gap unchanged. The direction note changes so that you can still tell which date came first. For a birthday calculation, use the age calculator instead: it expresses the interval as completed calendar years, months and days. For an event countdown, place the current comparison date first and the event date second, then leave inclusive counting off unless you want both dates included.
Frequently asked questions
Does the calculator include the start date?
By default it counts elapsed days and excludes the start date. Select Count both dates to count the start and end dates inclusively.
Can I enter the dates in reverse order?
Yes. The tool reports a nonnegative gap and states whether the end date is before the start date.
Does this count only business days?
No. It counts every calendar day, including weekends. It does not apply holiday calendars or business-day rules.