Days Between Two Dates Calculator
Calculate the number of days between two dates, with or without the bounds.
Enter a start date and an end date to run the calculation.
How is this result calculated?
The base calendar gap between the two dates is obtained by comparing their year/month/day components, then dividing the gap in milliseconds by the number of milliseconds in a day. This number corresponds to the start day being counted and the end day not being counted (like the number of nights of a stay between an arrival date and a departure date): this is the value used as-is when only one of the two bounds is included.
This total is then adjusted based on the chosen bounds: +1 day if both the first AND the last day are included (both bounds count), and −1 day if neither is included (neither counts). The displayed result never goes below 0.
Beyond 60 days of gap, an approximate equivalent in months and days is added for reference, calculated using an average calendar month length (30.44 days) — it does not replace the exact total in days shown above.
Frequently asked questions
What's the difference between including and excluding the bounds?+
Including a bound means counting the start day and/or the end day in the total. For example, from Monday to Friday: with no bound included, that's 3 days (Tuesday to Thursday); with both bounds included, that's 5 days (Monday to Friday); and with only one bound included, that's 4 days.
Why is the result in months approximate?+
Months don't all have the same length (28 to 31 days), so there is no exact conversion between days and months. The displayed equivalent uses an average length of 30.44 days per month, purely as an indication alongside the exact total in days.
How does the calculator handle a change of year?+
The calculation is based on the full calendar date (year, month, day) of each date, not on a simple day count within the year. A gap that spans one or more year boundaries, including a leap year, is therefore counted correctly.
Can this tool help me calculate a notice period or contractual deadline?+
Yes, that's a common use case: enter the notification date and the deadline to get the exact number of calendar days of notice or delay. Do check whether your contract defines the period in calendar days or business days, and adjust the inclusion of bounds to match the exact wording.
What's the difference with the business days calculator?+
This calculator counts every calendar day between two dates, including weekends and public holidays. The business days between two dates calculator excludes weekends (and French public holidays if needed) to give the number of days actually worked.