Date Difference
Total
About the Date Calculator
A date calculator finds the difference between two dates, or adds/subtracts days, weeks, months or years from a date. It handles the awkward bits — varying month lengths and leap years — so you don't have to count on a calendar.
Enter your dates or a date and a duration, and this tool computes the result in your browser. Useful for deadlines, ages, anniversaries and project planning.
How to use the Date Calculator
- 1To find a gap: pick a start date and an end date; read the difference.
- 2To shift a date: pick a date, enter a number of days/months/years to add or subtract.
- 3Read the resulting date or duration.
Common uses
Deadlines & due dates
Find the date N days from now, or days remaining until a deadline.
Ages & anniversaries
Work out an exact age or a milestone date.
Project planning
Add durations to a start date to schedule phases.
Frequently asked questions
Does it account for leap years?
Yes. Differences and additions handle leap years and varying month lengths correctly.
Are both endpoints counted in a difference?
The tool reports the number of days between the two dates; whether you count the end date is up to how you interpret the range.
Can I add months, not just days?
Yes — you can add or subtract days, weeks, months or years, and month arithmetic respects month lengths.
Is anything uploaded?
No. All date math happens in your browser.