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Date Difference Calculator

Calculate the difference between two dates

Start Date
End Date

About Date Difference Calculator

Calculate the exact gap between two dates in days, weeks, months, years, and business days simultaneously. Business days mode excludes weekends — useful for project planning and deadline calculations where working days matter. Add/subtract mode goes in the other direction: start from a date, add N days, find out what date that lands on. Common uses: project duration, contract lengths, how many days until something, how old something is.

Common Use Cases

  • →Calculating project duration from start to deadline
  • →Finding someone's exact age in years, months, and days
  • →Working out how many business days are left until a deadline
  • →Adding 90 days to a date to find the contract end date

Frequently Asked Questions

Are start and end dates included in the count?+
By default, exclusive — the days between, not including either endpoint. Toggle inclusive mode to count both the start and end day.
Do business days include public holidays?+
No — business day calculation excludes weekends only. Public holidays vary by country and are not excluded automatically. Subtract them manually.
Can I calculate an age?+
Yes. Set the start date to the birth date and the end date to today.