Times
Hours may be greater than 24. Minutes and seconds stay 0–59.
Result
How this time calculator works
There are two modes. The first adds or subtracts a duration: hours, minutes and seconds, like 2 h 30 min plus 1 h 45 min. Hours may go past 24 — extra time is also shown as days.
The second mode is a calendar gap: full years, then months, then leftover days, the same idea as an age calculator. Time zones are not converted. For “how old am I”, use the age page.
Clock time vs calendar months
A duration is exact seconds: 2:30:00 + 1:45:00 = 4:15:00.
Between dates, February and 31-day months matter. From 31 January to 1 March in a common year is 1 month and 1 day, not a raw count of 29 days labelled as a month.
Date difference counts completed years, then months, then days.
How to add times or compare dates
- Choose a mode: Times if you have hours and minutes. Dates if you have two calendar days.
- Enter the values: For times, add or subtract. For dates, start then end.
- Read the result: Clock as d HH:MM:SS, or years/months/days plus total days.
Frequently asked questions
Can hours be more than 24?
Yes. 30:00:00 is thirty hours. Extra hours are also split into days in the result.
How is the date difference counted?
Completed years, then months, then leftover days — like age. 15 January to 15 March is 2 months.
Does it include the end date?
It is end minus start at midnight. The same date is 0 days. 1 January to 2 January is 1 day.
Time zones?
No. Both fields are calendar dates, not instants in UTC.