Date Difference Calculator
Find how many days, weeks and years lie between any two dates.
How to use
- Pick the start date.
- Pick the end date.
- See the difference in days, weeks and years.
How the Date Difference Calculator works
Counts the days between two dates, and expresses the gap in weeks and years — for deadlines, notice periods, contract terms and anniversaries.
Both dates are converted to a timestamp, the difference is taken in milliseconds and divided into days. Years use 365.25 to average out leap years.
days = (date₂ − date₁) ÷ 86,400,000 ms
Worked example
From 1 January 2026 to 30 July 2026 is 210 days — about 30 weeks, or 0.58 years.
Things worth knowing
- The result is the count of days between the dates, exclusive. Contracts and notice periods often count inclusively, adding one day.
- Leap years are handled automatically because the calculation works from real timestamps rather than assuming a fixed year length.
- For very long spans, note that 365.25 is the Julian year; the Gregorian average is 365.2425, so century-scale results drift slightly.
Frequently asked questions
Does it count leap years?
Yes — it uses real calendar dates, so leap years are handled.
Can the second date be earlier?
Yes — it shows the absolute difference and notes when the second date comes first.
Does this count business days?
No, it counts calendar days including weekends and holidays.
Should the end date be included?
It depends on the context. Legal and rental periods frequently count both endpoints, which means adding one to this figure.