Date Difference Calculator
Find the number of days and weeks between any two dates. Great for deadlines, countdowns, and age calculations.
Weeks: 0.00
Common uses
Project deadlines
Count exact days remaining to a project due date or product launch.
Age in days
Enter your birth date to find your exact age in days (and weeks).
Event countdowns
Days until a wedding, vacation, holiday, or exam date.
Contract duration
Calculate how long a contract, subscription, or lease runs.
Days worked
Count calendar days between a start and end date for payroll or leave.
Time between events
How long since a past date — for anniversaries, elapsed time, or records.
How the calculation works
The calculator finds the difference in whole calendar days between the two dates, using midnight-to-midnight counting. January 1 to January 3 = 2 days, not 3.
Leap years are handled automatically. A year with 366 days (divisible by 4, except centuries not divisible by 400) adds one extra day in February. This matters for calculations spanning multiple years — for example, 2 years from Jan 1, 2024 (a leap year) = 731 days, not 730.
Weeks are calculated as days ÷ 7. To estimate months, divide days by 30.44 (the average calendar month length).
Frequently Asked Questions
This calculator counts midnight-to-midnight, so the result is the number of full calendar days between the two dates, not including both endpoints. For example, Jan 1 to Jan 3 = 2 days.