What the time calculator does
- Add / subtract: combine two durations, like 2 h 45 m + 1 h 30 m, with automatic carrying of seconds, minutes and hours.
- Between two times: the exact gap between two dates and times, for shifts, flights, events or deadlines.
- From now: what time it will be in X hours, or what time it was X hours ago, updated live.
- Convert: decimal hours to hours, minutes and seconds, and back.
How time math works
Time uses base 60: 60 seconds make a minute and 60 minutes make an hour, while 24 hours make a day. The calculator converts everything to seconds, adds or subtracts, then converts back.
Example: 2 h 45 m + 1 h 30 m = 9,900 s + 5,400 s = 15,300 s, which is 4 h 15 m.
Common time conversions
| Time | Hours | Minutes | Seconds |
|---|---|---|---|
| 1 day | 24 | 1,440 | 86,400 |
| 1 week | 168 | 10,080 | 604,800 |
| 30 days | 720 | 43,200 | 2,592,000 |
| 1 year (365 days) | 8,760 | 525,600 | 31,536,000 |
Frequently asked questions
How do I add hours and minutes?
Add the minutes first. If they reach 60 or more, carry one hour for every 60 minutes. For example, 2 h 45 m + 1 h 30 m = 3 h 75 m, which is 4 h 15 m. The calculator also carries seconds into minutes and hours into days.
How do I find the time between two times?
Use the "Between two times" tab. Enter the start date and time and the end date and time, and the calculator shows the gap in days, hours, minutes and seconds, plus totals in hours, minutes and seconds.
What time will it be in 8 hours?
Use the "From now" tab, enter 8 hours and choose "from now". The answer updates every second and shows the date too if it crosses midnight.
How do I convert decimal hours to hours and minutes?
Multiply the decimal part by 60. For example, 7.75 hours is 7 hours and 0.75 × 60 = 45 minutes. The Convert tab does both directions.
Does the time between two times include daylight saving changes?
Yes. When you enter dates and times, the calculator uses your device clock rules, so a span that crosses a daylight saving change is one hour shorter or longer than the clock times suggest.