Date Difference Calculator interactive tool
0 years, 1 months, and -1 days
What Is Date Difference?
A date and time calculator helps you count calendar days without doing the arithmetic by hand. Use it to find the number of days between two dates or to add a specific number of days to a date.
Handling Calendar Complexities
Calculating date differences manually is notoriously difficult due to:
- Varying Month Lengths: Months have 28, 29, 30, or 31 days.
- Leap Years: The addition of February 29th every four years.
Common Use Cases
Common uses include project planning, event planning, and checking a calendar-day deadline. For legal or financial deadlines, confirm whether the relevant rule uses calendar days, business days, or an inclusive count.
How To Use the Date Difference Calculator
- Choose whether you want to find the difference between two dates or add/subtract days from a date.
- Enter your starting date and the target date (or number of days).
- Review the total days and, when shown, the calendar years, months, and days.
Days between dates and adding days
This date difference calculator finds the number of days between two calendar dates and can also add or subtract days from a starting date. It accounts for leap years and different month lengths.
Need the formula or convention behind this result? Read the calculator methods and assumptions.