Time & Date
Days Between Dates
Find the exact number of days, weeks, and months between two dates.
Compute precise gaps between any two dates — useful for project deadlines, contract durations, gestation tracking, and historical comparisons.
Day Difference
366 days
- weeks
- 52.3 weeks
- months
- 12.0 months
- years
- 1.00 years
Formula and method
Days = (End Date - Start Date) in milliseconds / 86,400,000
Uses Unix timestamps; accounts for leap years automatically.
Worked examples
One year
- Start Year:
- 2024
- Start Month (1-12):
- 1
- Start Day:
- 1
- End Year:
- 2025
- End Month (1-12):
- 1
- End Day:
- 1
Day Difference: 366 days
Assumptions and limits
- Gregorian calendar
This tool provides an educational estimate. Rules, rates and personal circumstances can change the answer. Review the assumptions before relying on a result. Report a correction.
Common mistakes to avoid
- Confusing inclusive vs exclusive day counts.
- Forgetting Feb 29 in leap years.
Frequently asked questions
Inclusive or exclusive?
This calculator returns the elapsed days (exclusive of start day). Add 1 if you need inclusive counts.