Date Calculators
The duration between two dates broken down every way — total days, weeks, years/months/days, business days and working hours — plus date arithmetic (add or subtract days, weeks, months or years, optionally skipping weekends) and a two-way Unix timestamp converter.
Why date arithmetic is hard
Adding "one month" to 31 January has no single right answer — is it 28 February, or 3 March? Daylight-saving transitions mean some local days are 23 or 25 hours long, so adding 24 hours is not the same as adding one day. This calculator works in whole calendar days in your local zone and clamps month-end overflow, which matches what most people expect.