Date Calculator – Days Between Dates
Our Date Calculator helps you find the exact number of days, weeks, months, and years between any two dates. You can also add or subtract days from a specific date to find future or past dates.
How to Use the Date Calculator
Calculate Duration Between Dates
- Select "Between" mode
- Enter your start date
- Enter your end date
- Choose whether to include the end date in the count
- View results in days, weeks, months, and business days
Add or Subtract from a Date
- Select "Add" or "Subtract" mode
- Enter your starting date
- Enter days, weeks, months, and/or years to add or subtract
- View the resulting date and day of the week
Common Date Calculations
Project Deadlines
Calculate how many days you have until a deadline, or find a date that's 30, 60, or 90 days from today.
Contract Durations
Determine the exact length of contracts, leases, or agreements. Calculate renewal dates or notice periods accurately.
Vacation Planning
Count how many days of vacation you're taking, including or excluding weekends and holidays.
Age Calculations
Find exact time between dates for age verification, eligibility calculations, or milestone planning.
Business Days vs Calendar Days
What Are Business Days?
Business days (also called working days) are Monday through Friday, excluding weekends. Our calculator automatically counts business days for you.
Note: Public holidays are not automatically excluded as they vary by country and region. Subtract these manually if needed.
When to Use Business Days
- Shipping and delivery estimates
- Legal notice periods
- Bank processing times
- Project timelines in work settings
Understanding Date Calculations
Include End Date Option
Include End Date: Counts both the start and end dates. Use this for vacation days, event durations, or when counting "inclusive" days.
Exclude End Date: Counts days between but not including the end date. This is the mathematical difference between dates.
Examples
- January 1 to January 3 (include end): 3 days
- January 1 to January 3 (exclude end): 2 days
Frequently Asked Questions
How are months calculated when adding to a date?
Adding months moves to the same day of the target month. If that day doesn't exist (e.g., January 31 + 1 month), it adjusts to the last valid day (February 28 or 29).
Does this account for leap years?
Yes! Our calculator correctly handles leap years. February has 29 days in leap years (years divisible by 4, except century years not divisible by 400).
How do I calculate 90 days from today?
Select "Add" mode, enter today's date as the start date, then enter 90 in the days field. The calculator will show you the exact date and day of the week.
Why are business days different from total days?
Business days exclude Saturdays and Sundays. A 2-week period has 14 calendar days but only 10 business days.
Can I calculate dates in the past?
Yes! Use the "Subtract" mode to find past dates, or enter an older start date to calculate historical durations.
How do I calculate weeks between dates?
The calculator automatically shows weeks. For partial weeks, divide the total days by 7.
Calculate Your Dates Now
Use our free Date Calculator for all your date math needs. Whether you're planning a project, counting down to an event, or calculating deadlines, this tool provides instant, accurate results.