Calculate the exact number of days, weeks, months, and years between any two dates. Includes business days, weekend days, total hours, minutes, and seconds. Perfect for project planning, legal deadlines, event countdowns, age calculations, and contract periods.
Quick presets
Tuesday, March 17, 2026
Thursday, April 16, 2026
= 4 wk + 2 days
A date difference calculator computes the exact span of time between two calendar dates — expressed in years, months, weeks, days, hours, minutes, and seconds. It's an indispensable tool for project planning, legal deadlines, age calculations, event countdowns, and any situation where you need to know precisely how much time separates two dates.
Total Days = |endDate − startDate|
(measured in whole calendar days)The absolute difference between the two dates in days, always non-negative. Leap years are included because we subtract actual timestamps, not assumed 365-day years.
From 'from' date, add the largest whole
years that fit → then months → then
floor(remaining/7) weeks → remaining daysWorks like counting on a real calendar. Adding '1 year' moves the date to the same day next year, correctly handling February and month-length differences.
fullWeeks = floor(total / 7)
bizDays = fullWeeks × 5
+ count Mon–Fri in remainder daysCounts Mondays through Fridays only. Public holidays are not subtracted since they vary by country and region. For precise work-day deadlines, subtract your local holidays manually.
Hours = totalDays × 24
Minutes = Hours × 60
Seconds = Minutes × 60Converts calendar days to smaller time units assuming exactly 24 hours per day. DST transitions are not included — for time-zone-sensitive work, use a dedicated timezone calculator.
Jan 1, 2025 → Jan 31, 2025Sep 15, 2024 → Mar 15, 2025Jun 10, 1990 → Jun 10, 2025Today → Dec 25, 2025Date Difference Calculator is part of the Time & Date collection. If you want a broader view of similar workflows, open the Time & Date category page or browse all QuickTools categories.
Common next steps after this tool include Time Zone Converter, Time Duration Calculator and Age Difference Calculator.
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