Date Interval Calculator
Measure an interval between two dates
The interval in every unit at once, plus its midpoint, its ISO 8601 duration string and the calendar breakdown — one page for measuring a span and quoting it.
Questions people ask
The things that come up about date interval calculators, answered plainly.
What is an ISO 8601 duration?
A machine-readable span: P1Y2M3DT4H5M6S is one year, two months, three days, four hours, five minutes and six seconds. The P starts it and the T separates the date part from the time part.
What is the midpoint for?
The instant exactly halfway between the two — useful for splitting a booking, finding the middle of a project, or scheduling a check-in.
Related tools
How far apart two instants are — in whichever unit you need, counting every day or only the working ones.
Time Interval CalculatorA clock-focused interval: hours, minutes and seconds first, the decimal hours payroll wants, and the ISO 8601 form for anything machine-readable.
Duration CalculatorA duration in every unit from nanoseconds to decades, with the approximate ones flagged as approximate — because a month has no fixed length and any tool that pretends otherwise is guessing.
Date Difference CalculatorEnter two dates and get the gap in every unit at once — years, months and days as a person would say it, and the exact total in weeks, hours, minutes and seconds underneath.
Date Duration CalculatorThe duration of a range stated the way a person would state it, plus the exact totals underneath and a census of which weekdays fall inside it.