Days Between Dates Calculator

Count the days between two dates

Add or subtract days from a date

How the days-between-dates calculation works

The calculator converts both dates to a day count (using UTC, so daylight saving time can never add or steal an hour) and subtracts. That gives the exact number of midnights between the two dates — the standard difference. If you need a count that includes both the first and last day (common for deadlines, rentals, and billing), choose the inclusive option, which adds one. Business days are counted by walking the range and tallying only Monday through Friday; weekends are the rest. The years/months/days figure is a calendar breakdown: full years first, then full calendar months, then the remaining days.

Adding days works the same way in reverse: the day count is increased by the number you enter and converted back to a calendar date, correctly rolling over month lengths, leap years, and year boundaries.