Add Time to Date Calculator
Add years, months, weeks, days, hours, minutes and seconds to a start date and time, then see the resulting date-time and total offset.
Add Time to Date Calculator
Total offset
How it was calculated
Add time to a date and time
This tool covers the English date-time arithmetic intent: start with a date and clock time, add a mixed duration, and see the resulting date and time after rollovers.
Delta T can include years, months, weeks, days, hours, minutes and seconds. Calendar units are applied before clock units.
Local time and rollover notes
- Years and months are calendar units, so month length matters.
- Hours, minutes and seconds roll over into the next day when needed.
- The calculation uses the browser's local time zone; daylight-saving transitions can affect real elapsed clock hours.
Frequently Asked Questions
Sources and References
- DateMDN Web Docs
- Representing dates and timesMDN Web Docs
- Gregorian calendarBritannica
- SI Units: TimeNIST
- Date Calculatortimeanddate.com
Calculations are based on the listed reference sources. Links open in a new tab.
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