Time Unit Converter
Convert between seconds, minutes, hours, days, weeks, months, and years instantly.
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How to use this calculator
- 1
Enter the time value you want to convert.
- 2
Select the unit you are starting from (e.g. hours).
- 3
Select the unit you want to convert to (e.g. minutes).
- 4
The result appears instantly.
Frequently asked questions
How many seconds are in a day?
There are 86,400 seconds in a day (60 seconds × 60 minutes × 24 hours).
How many hours are in a year?
A standard year has 8,760 hours (365 days × 24 hours). A leap year has 8,784 hours.
How many milliseconds are in a second?
There are exactly 1,000 milliseconds in one second.
How many weeks are in a year?
A year has 52 weeks and 1 day (or 2 days in a leap year), totalling exactly 52.1775 weeks on average.
How long is a nanosecond?
A nanosecond is one billionth of a second (10⁻⁹ s). In that time, light travels about 30 centimetres — roughly one foot.
Time unit conversion explained
SI and everyday time units
The SI base unit of time is the second. All other units — milliseconds, minutes, hours, days — are derived from it. The second is defined by the vibration of caesium-133 atoms (9,192,631,770 cycles per second), making it one of the most precisely defined units in science.
Key time conversion facts
1 minute = 60 seconds | 1 hour = 3,600 seconds | 1 day = 86,400 seconds | 1 week = 604,800 seconds | 1 year = 31,536,000 seconds (365 days) | 1 millisecond = 0.001 seconds | 1 microsecond = 0.000001 seconds.
When time conversions are needed
Time unit conversions are common in programming (converting timestamps), science experiments (measuring reaction times in milliseconds), project management (estimating hours vs days), payroll calculations (hours worked vs days), and data analysis (log file timestamps).
Learn more from an authoritative source:
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →