What is a Time Unit Converter?
The time unit converter switches between seconds, minutes, hours, days, weeks, months, and years.
How it's calculated
1 minute = 60 seconds, 1 hour = 3,600 seconds, 1 day = 86,400 seconds. A year is calculated as 365 days (366 in a leap year).
Why base-60?
The origin traces back roughly 4,000 years to Mesopotamia. The number 60 has an unusually large number of divisors (1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60), meaning 1/2, 1/3, 1/4, 1/5, and 1/6 all divide evenly โ an enormous advantage in an era without decimal fraction notation.
Dividing the day into 24 hours came from Egypt, splitting day and night into 12 parts each โ 12 being the number of finger joints you can count using your thumb as a pointer.
Good to know
- Angles also use base-60 โ 1 degree = 60 minutes = 3,600 seconds. The overlap between time and angle notation traces back to shared Babylonian astronomical roots, including the 360-degree circle based on roughly 360 days in a year.
- Months never divide evenly โ the lunar cycle is 29.53 days, which fits neither 30 nor 31 evenly, and February's odd length is a residue of adjustments made to reconcile this.
- A second is defined by the cesium atom โ specifically, 9,192,631,770 oscillations of a particular electron transition in cesium-133, chosen because Earth's rotation is not perfectly regular.
- That irregularity occasionally requires a leap second, which has caused enough system errors that it's scheduled to be phased out by 2035.
- 1 year โ ฯ ร 10โท seconds, off by only about 0.4% โ a handy approximation physicists actually use for quick mental math.
Frequently asked questions
Q. How many seconds are in a year?
31,536,000 seconds for 365 days; 31,622,400 for a leap year.
Q. How is a month typically counted in days?
Either 30 days, or an average of 30.44 days (365รท12), depending on the use case. For precise calculations, use actual calendar dates.
Q. What is a millisecond or microsecond?
1 millisecond = 1/1,000 second; 1 microsecond = 1/1,000,000 second.