WhenMathTime Midpoint Calculator
Find the exact halfway point between a start and an end. Use clock mode for a same-day span, or date and time zone mode when the span crosses a daylight-saving transition and you want the real elapsed midpoint rather than the wall-clock middle.
Worked example
Between 09:00 and 17:00, the span is 8 hours, so the midpoint is 4 hours after the start: 13:00. For an overnight span like 22:00 to 06:00 the next day, the span is 8 hours (crossing midnight), and the midpoint is 4 hours after 22:00, which is 02:00 the next day.
Wall-clock midpoint versus elapsed midpoint
In America/New_York on March 14, 2027, the span from 00:00 to 04:00 looks like a 4-hour span on the clock, but because clocks spring forward at 2:00 AM, only 3 hours of real time actually pass. The elapsed midpoint (halfway through the real 3 hours) lands at 01:30, not the wall-clock-naive 02:00. Date and time zone mode always computes the elapsed midpoint and flags when a transition affects the result.
Limitations
This is a clock and calendar calculation only; it does not schedule a meeting or notify anyone.
Frequently asked questions
- Which mode should I use?
- Use clock mode for a simple same-day span. Use date and time zone mode whenever the span might cross a daylight-saving transition.