Date Calculator — Days Between Dates & Date Add/Subtract
Calculate the exact number of days between two dates — or jump forward and backward on the calendar with precision. Project deadlines, visa processing times, pregnancy weeks, exam countdowns, notice periods and invoice terms all come down to “how many days between these two dates?” — and counting on your fingers across month boundaries is where errors creep in. This date calculator handles the gap in both directions, breaks it down into weeks and days, counts business days excluding weekends, and can add or subtract any combination of years, months, weeks and days from a starting date. Leap years and month lengths are handled automatically.
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How to calculate days between dates online for free
- 1
Choose a mode: “Days between dates” or “Add/subtract from a date”.
- 2
For date differences, enter the start and end dates — the total days, weeks and business days appear instantly.
- 3
For date math, enter a start date and the years, months, weeks or days to add or subtract.
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Review the result date or duration breakdown, and adjust any input to recalculate live.
Why use this date calculator tool?
Exact day counts
Total days, total weeks plus days, and business days (weekends excluded) — calculated with full leap-year and month-length accuracy.
Add or subtract time
Combine years, months, weeks and days in one operation to find deadlines, due dates and expiry dates precisely.
Both directions
Enter dates in either order — the calculator reports the absolute gap, so end-before-start never breaks anything.
Live recalculation
Every field updates results instantly, making it easy to explore “what if” scenarios like different start dates or notice periods.