Time since a date
Calculate days, hours, minutes and seconds since, until or between dates.
How to use
Measure the distance between two dates, or from a date to now, in days, hours, minutes and seconds — for a deadline, an age, a contract term or a countdown.
Days are the safe unit; months are not. A month has no fixed length, so adding one to 31 January has no single correct answer and different systems give different ones. Hours have their own trap: in countries that still change the clocks, one day a year is 23 hours and another is 25, which is why the hours between two dates can disagree with the days multiplied by 24. Brazil dropped daylight saving in 2019, most of Europe still has it.
Example
Two datesThe exact number of days, and the same span in hours.A date to nowA running countdown or count-up.A span crossing a clock change23 or 25 hours in that day, where DST applies.
Frequently asked questions
Why does the number of months not match what I expected?
Because months differ in length and there is no agreed rule for the ends. From 31 January to 28 February is one month by one convention and not quite one by another. Where a figure has to be defensible — a contract, an invoice — count in days, which are never ambiguous.
Is a day always 24 hours?
Not everywhere. Where daylight saving is observed, the day the clocks go forward is 23 hours and the day they go back is 25. A difference measured in hours and a difference measured in days can therefore disagree by an hour, and both are correct.