Quick answer: 1 day 2 hours 30 minutes plus 5 hours 45 minutes 30 seconds is 1 day 8 hours 15 minutes 30 seconds, which is 32.2583 hours.
How it's calculated
Each length of time is turned into seconds: days × 86,400 + hours × 3,600 + minutes × 60 + seconds. The two totals are added or subtracted, and the answer is split back into days, hours, minutes and seconds, carrying every 60 seconds into a minute, 60 minutes into an hour and 24 hours into a day.
You can type more than 59 minutes or 23 hours, or decimals such as 1.5 hours; they are carried over the same way. If the second time is larger when subtracting, the result is shown with a minus sign.
For dates on a calendar rather than lengths of time, use add days to a date or days between two dates.
Worked examples
- 1 d 2 h 30 min + 5 h 45 min 30 s: 95,400 + 20,730 = 116,130 s = 1 d 8 h 15 min 30 s
- 8 h 15 min − 2 h 50 min: 29,700 − 10,200 = 19,500 s = 5 h 25 min
- 90 min + 45 min: 5,400 + 2,700 = 8,100 s = 2 h 15 min
Frequently asked questions
How do I add hours and minutes by hand?
Add the minutes, and for every 60 minutes carry 1 hour; then add the hours. 2:45 + 1:30 is 3 hours 75 minutes, which is 4 hours 15 minutes.
How do I turn minutes into decimal hours?
Divide the minutes by 60: 15 minutes is 0.25 hours, 45 minutes is 0.75 hours. The result here also shows total hours as a decimal.
Can I subtract a larger time from a smaller one?
Yes. The answer is the difference with a minus sign, for example 2 hours − 3 hours 30 minutes = −1 hour 30 minutes.
How many seconds are in an hour and a day?
3,600 seconds in an hour and 86,400 in a day.
What happens when minutes go over 60?
They carry into hours, as seconds carry into minutes and hours carry into days. 45 minutes plus 30 minutes gives 1 hour 15 minutes.
Does a day here always mean 24 hours?
Yes. It adds lengths of time and doesn't use a calendar. To add time to an actual date, use the date tools.