Date Difference Calculator - Days Between Two Dates
Calculate the number of days, weeks, months, and years between any two dates. Includes business-day mode, weekend handling, and age in years/months/days.
Interactive Date Difference Calculator - Days Between Two Dates
Date Difference Calculator - Days Between Two Dates
Results
The date-difference calculator answers three recurring questions: how many days between two events, how many business days (excluding weekends), and how old someone was on a specific past date. All three work with the same two date inputs and toggleable options.
What This Calculator Does
Enter a start date and an end date. The calculator returns:
- Total days, weeks, months, and years between them
- Business days (Mon-Fri only) if the toggle is on
- Calendar days (default — every day counts)
- End date relative to today (e.g. “in 47 days”, “185 days ago”)
- Year/month/day breakdown (e.g. 4 years, 2 months, 11 days)
Quick Example: 2020-01-15 to 2026-07-08
- Total days: 2,366
- Weeks: 338
- Business days: ~1,690 (after excluding 338 weekend days)
- Years/months/days: 6 years, 5 months, 23 days
- Relative: “1,393 days ago” (calculated against current date)
Business-Day Mode
Toggle Business days only to exclude weekends:
- Mon-Fri count as workdays
- Sat-Sun are skipped
- U.S. federal holidays are NOT excluded by default
Toggle Exclude US holidays to also skip:
- New Year’s Day (Jan 1)
- MLK Day (3rd Mon Jan)
- Presidents’ Day (3rd Mon Feb)
- Memorial Day (last Mon May)
- Juneteenth (Jun 19)
- Independence Day (Jul 4)
- Labor Day (1st Mon Sep)
- Columbus Day (2nd Mon Oct)
- Veterans Day (Nov 11)
- Thanksgiving (4th Thu Nov)
- Christmas (Dec 25)
The holiday list reflects federal U.S. holidays. If you need a different country, edit the holidays.json data file (we keep it minimal for performance).
Use Cases
- Project planning: “How many business days from kickoff to launch?”
- Visa / immigration: “How many days have I been in the Schengen zone this 180-day window?”
- Pregnancy / due date: “How many weeks since last menstrual period?”
- Tenancy: “How many days until my lease ends?”
- Legal deadlines: “How many business days do I have to respond to this filing?”
Limitations
- The calculator does not handle BC dates (BCE). For historical dates before 1582 (Gregorian reform), results are estimates.
- It assumes the Gregorian calendar; if you need Julian or other calendars, use a dedicated tool.
Related Tools
- Age Calculator — age at today’s date
- Time Calculator — hours and minutes
- BMI Calculator — health metrics
Frequently Asked Questions
How do I count only business days between two dates?
Toggle 'business days only' and the calculator excludes weekends (Sat/Sun). Federal U.S. holidays are not excluded by default — toggle 'exclude US holidays' to skip the 11 federal holidays as well.
Does the calculator handle leap years correctly?
Yes. The day count uses the proleptic Gregorian calendar, which accounts for leap years in 1900-2099. The Feb 29 day is correctly included or excluded based on the date range.
Can I calculate someone's age at a past date?
Yes. Set the start date to their birthdate and the end date to any past or future date. The result shows years, months, days, and total days — same as the age calculator.
What if the end date is before the start date?
The calculator returns a negative result and shows the absolute value alongside. Useful for finding how long ago a past event was (e.g. 'since 2010').