Date Difference Calculator
Calculate the number of days, weeks, months, and years between two dates.
The starting year.
The starting month (1-12).
The starting day of the month.
The ending year.
The ending month (1-12).
The ending day of the month.
How to Calculate Days Between Two Dates
This calculator finds the exact difference between any two dates. It handles leap years, varying month lengths, and dates spanning centuries. The result is shown both as a total (days, weeks, months) and as a breakdown (X years, Y months, Z days).
The order of dates doesn't matter — the calculator always shows the absolute difference.
Common Date Calculations
People frequently need to calculate date differences for:
- Project deadlines: How many working days until a due date.
- Age verification: Exact age in years, months, and days.
- Pregnancy tracking: Days since conception or until due date.
- Lease and contract terms: Exact duration of rental or employment periods.
- Event countdown: Days until a wedding, vacation, or graduation.
- Historical research: Time elapsed between historical events.
Leap Years and Calendar Quirks
A year has 365 days — except leap years, which have 366. Leap years occur every 4 years, except for century years (1900, 2100) which are not leap years, unless divisible by 400 (2000 is a leap year). This is why precise date math is tricky to do by hand.
Month lengths also vary: 28-31 days. February has 28 days (29 in leap years). April, June, September, and November have 30. All others have 31.