Calculate the difference between dates, find your exact age, or count down to important events. Multiple output formats available.
Calculate the difference between two dates in multiple formats.
Saved Presets is a Supporter feature.
Tool Notes is a Supporter feature.
Select a start date and end date to see the difference in years, months, weeks, and days
Enter your birth date to see your exact age and days until your next birthday
Enter an event name and date to see how many days until that event
The calculator uses JavaScript's Date object to perform precise date arithmetic, accounting for varying month lengths and leap years.
By default, the calculator counts days between dates (exclusive). Enable 'Include end date' to count both the start and end dates (inclusive counting).
Date calculations use JavaScript's Date object which represents time as milliseconds since January 1, 1970 (Unix epoch). Adding/subtracting days converts to milliseconds (1 day = 86,400,000 ms), while month/year operations handle varying lengths correctly.
Finding the difference between dates involves calculating years first, then remaining months, then remaining days. This accounts for month length variations (28-31 days) and leap years, giving you human-readable durations like '2 years, 3 months, 15 days'.
The calculator computes the exact difference by subtracting dates, then breaks down the total into years, months, weeks, and remaining days.
