Date Calculators

Date arithmetic looks simple until a month boundary, a leap year or a weekend gets in the way. These calculators do the counting for you and show how the answer was reached: how many days lie between two dates, what date it will be a set number of days from now, and when a half birthday falls.

All of them work on calendar days, so a change to or from daylight saving time never adds or drops a day. Where working days are counted, weekends are left out and you can also leave out US federal holidays, including the Friday or Monday on which a weekend holiday is observed.