Formula
1 min = 60 s; 1 h = 3,600 s; 1 day = 86,400 s1 week = 7 days1 year (Gregorian average) = 365.2425 days1 month (average) = 1/12 year = 30.436875 days How it works
Seconds, minutes, hours, days and weeks convert with fixed factors: 60, 60, 24 and 7. The second itself is defined by atomic clocks as 9,192,631,770 oscillations of a caesium-133 atom.
Months and years are not fixed lengths. Here a year is the average Gregorian calendar year of 365.2425 days — the value that keeps leap years in step over a 400-year cycle — and a month is one twelfth of that, about 30.44 days. For a specific span of calendar dates, use the date difference calculator instead.
The last output splits the total into days, hours, minutes and seconds, which is easier to read for large numbers of seconds or minutes.
Frequently asked questions
How many seconds are in a day?
86,400 (24 × 60 × 60), ignoring the occasional leap second.
How many hours are in a year?
8,760 in a 365-day year and 8,784 in a leap year. The average Gregorian year is 8,765.82 hours.