Time Between Two Dates

What the time between two dates tool does

This one is for when whole days are not enough and you need the time down to the minute. Where a days calculator stops at the date, this tool takes a start and an end with the clock time included, and works out the exact span between the two moments. Then it shows you that span expressed every way at once, in years, months, weeks, days, hours, minutes, and seconds.

Because it carries the time of day, it is the right tool for an exact answer: how long since something happened to the minute, or the precise gap between two timestamps.

How to use it

1. Start Date and Time. Pick the starting date, then the time of day next to it.
2. End Date and Time. The same for the later moment.

Press Calculate, and the full set of figures appears. Press Reset to clear them.

How the duration is worked out

It joins each date to its time to make two exact moments, then measures the gap between them as a number of seconds. From that single gap it works out every other unit: how many whole minutes fit in it, how many whole hours, how many whole days, and so on up to years. The order of the two moments does not matter, since it always takes the size of the gap, never a negative.

Why it shows the same gap in every unit

This is the thing to understand about the result, because it reads differently from a normal age-style breakdown. The figures are not meant to be added together. Each line is the whole gap expressed in that one unit. So a span might show as 2 days, and also as 48 hours, and also as 2,880 minutes. Those are not three separate pieces of the answer, they are the same length of time measured three different ways. You read the line for whichever unit you happen to need, rather than stacking them up.

An example with real numbers

Say the gap works out to 2 days and 12 hours. Here is how that same span lands across the units:

• Full days: 2
• Full hours: 60
• Full minutes: 3,600
• Seconds: 216,000

Every one of those describes the identical 2-and-a-half-day gap. Sixty hours is the same as two and a half days, and 216,000 seconds is the same again, just counted in smaller pieces.

Which figures are exact, and which are close

One honest point about the longer units. Days, hours, minutes, and seconds are exact, because they are fixed sizes that never change. Years and months are a little different. Months come in four different lengths and a year is sometimes 365 days and sometimes 366, so to express a gap in those units the tool uses their average lengths, about 30.44 days for a month and 365.25 days for a year. For a short span that hardly matters, and for a rough sense of a long one it is fine, but if you need a precise years-and-months answer for something like an exact age, a calendar-based age calculator that walks the real months is the better fit. The day, hour, minute, and second figures here are spot on either way.

Questions people ask

How is this different from a days between dates tool?

A days tool works in whole calendar days and ignores the time of day. This one takes the clock time as well, so it can give you the gap down to the second, and it shows that gap in every unit from years to seconds.

What does "full" hours or minutes mean?

It means complete units only. If a gap is 60 minutes and 40 seconds, the full minutes figure is 60, because the leftover 40 seconds have not made another whole minute. The seconds line carries the exact total.

Are the years and months exact?

No, those two are based on average lengths, since real months and years vary in size. The days, hours, minutes, and seconds are exact. For a precise years-and-months result, use a calendar-based age or duration tool.

Does it matter which date I put first?

No. The tool always reports the size of the gap, so entering the later moment first gives you the same answer.

References

1. U.S. Naval Observatory, Astronomical Applications Department: Leap Years, on the length of the year. https://aa.usno.navy.mil/faq/leap_years