What this calculator does
Calculate signed elapsed time between two dates and clock times.
How it works
The calculator evaluates elapsed milliseconds = end date-time − start date-time. Inputs are checked before calculation, and invalid values such as zero denominators or out-of-range selections produce a clear error instead of a misleading result.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
4-
?startDate=Start dateDate · Required · Default: 2026-09-01
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?startTime=Start timeTime · Required · Default: 09:00
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?endDate=End dateDate · Required · Default: 2026-09-03
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?endTime=End timeTime · Required · Default: 17:30
Outputs
5-
durationElapsed durationText · Primary output
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totalDaysTotal daysNumber
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totalHoursTotal hoursNumber
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totalMinutesTotal minutesNumber
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totalSecondsTotal secondsWhole number
Inputs and results
The inputs are Start date, Start time, End date, End time. Results include Elapsed duration, Total days, Total hours, Total minutes, Total seconds.