Home Calculators Days Calculator: Days Between Two Dates. Days Calculator: Days Between Two Dates. How many days, months, and years are there between two dates?. Instantly add or subtract time spans (days, weeks, months, years, hours, minutes, seconds) to or from dates with this free online date time calculator. Add or subtract days, weeks or months from a given date - simple and quick date calculations. Add times The Add time fields link takes you to the Time Duration Calculator where you can add hours, minutes, and seconds to your calculation. Although the total number of days in January 31 and February 28 are different, both are to and from dates as 1 month. If you do discover an issue with the calculated results, please report the issue using the feedback form located below the calculator. Enter the number of each time span you would like added or subtracted. The Make adjustment and calculate again is a shortcut to the top of the page.