When this tool helps
- Measure the gap between two dates
- Check how many days remain before a deadline
- Compare a project start and finish date
DATE & TIME
Date Difference Calculator
Count the exact days and weeks between two dates.
Runs locallyNothing is uploaded
PRACTICAL GUIDE
How to use Date Difference
Last reviewed
Find the difference between two calendar dates as total days and complete weeks. The calculator uses date-only values, so daylight-saving clock changes do not add or remove an hour from the result.
How to use it
- Enter the earlier or starting date
- Enter the later or ending date
- Read the signed day difference and complete-week equivalent
- Use the working-days tool when weekends must be excluded
Difference between two dates
- Input
- 1 September 2026 to 15 September 2026
- Result
- 14 days, or 2 complete weeks
The start date is not counted as an elapsed day. Reversing the dates produces the same magnitude in the opposite direction.
Formula: day difference = (end date at UTC midnight - start date at UTC midnight) / 86,400,000
Limits and assumptions
- This is calendar arithmetic, not a legal deadline interpretation
- Public holidays are not excluded
- Time-of-day and time-zone offsets are intentionally ignored
Frequently asked questions
Is the start date included?
The result measures elapsed boundaries between dates, so identical dates equal zero days.
Can I calculate between two dates in reverse order?
Yes. The direction indicates whether the second date is before or after the first.
Does this count business days?
No. Use the Working Days Calculator to exclude Saturdays and Sundays.