Converter category
Time Converter
Convert between nanoseconds, microseconds, milliseconds, seconds, minutes, hours, days, weeks, fortnights, months, quarters, years, decades, centuries, millennia, sidereal days, and Julian years.
Universal Time Converter
About time conversions
Time conversions help you plan schedules, calculate durations, convert workout intervals, and understand historical or scientific periods. Our time converter covers tiny fractions like nanoseconds and microseconds, everyday units such as seconds, minutes, hours, and days, and larger spans including weeks, fortnights, months, quarters, years, decades, centuries, and millennia. It also includes specialized units like sidereal days and Julian years for astronomy. Every conversion uses exact definitions, so you can trust the result whether you are timing an event, planning a project, or studying celestial cycles.
Available units
Popular time conversions (15 total)
Unit definitions
Nanosecond (ns)
1 ns = 10^-9 seconds. Light travels ~30 cm in 1 ns.
Origin: Metric prefix nano- = 10^-9.
Current use: Computing, Telecommunications, Physics
Microsecond (µs)
1 µs = 10^-6 seconds.
Origin: Metric prefix micro- = 10^-6.
Current use: Electronics, Signal processing, Physics
Millisecond (ms)
A millisecond is one thousandth of a second. A typical camera flash lasts about 1 millisecond.
Origin: Part of the metric system where milli- denotes one-thousandth.
Current use: Computer processing, Sports timing, Scientific experiments
Second (s)
The second is the SI base unit of time. It is defined by the radiation cycles of a cesium atom.
Origin: Originally 1/86,400 of a mean solar day. Since 1967, defined by the cesium atomic clock.
Current use: Scientific measurements, Sports timing, Computing
Minute (min)
A minute is exactly 60 seconds. It is commonly used for measuring short time intervals.
Origin: From the Latin pars minuta prima, meaning first small part. Divided the hour into 60 minutes.
Current use: Meetings and appointments, Cooking times, Travel durations
Hour (h)
An hour is exactly 60 minutes or 3600 seconds. There are 24 hours in a day.
Origin: From the Egyptian division of the day into 24 hours, each corresponding to one-twelfth of the daylight period.
Current use: Work schedules, Travel times, Media consumption
Day (d)
A day is approximately 24 hours or 86,400 seconds. It is based on Earth's rotation.
Origin: Originally based on the rotation of Earth relative to the Sun. Now defined by SI seconds.
Current use: Calendar systems, Work weeks, Biological cycles
Week (wk)
A week is exactly 7 days or 168 hours. Used globally for work schedules and planning.
Origin: Based on the Judeo-Christian tradition of rest on the seventh day. Seven-day week has been used for over 2,000 years.
Current use: Work schedules, Project planning, Recurring events
Fortnight (fn)
A fortnight is exactly 14 days or 2 weeks, used mainly in UK and Ireland.
Origin: Contracted from 'fourteen nights'. Common British usage.
Current use: UK billing cycles, Subscription services, Historical usage
Month (mo)
A month is approximately 30.44 days, based on the lunar cycle. Months have 28-31 days.
Origin: Derived from the lunar cycle, approximately 29.5 days. Roman calendar had 10 months.
Current use: Calendar planning, Billing cycles, Contract durations
Quarter (quarter)
A quarter is 3 months or approximately 91.25 days. Four quarters make a year.
Origin: Used in business and finance for reporting periods.
Current use: Financial reporting, Business planning, Fiscal calendars
Year (yr)
A year is approximately 365.25 days, the time for Earth to orbit the Sun once.
Origin: Originally based on Earth's rotation around the Sun. Julian calendar introduced 45 BCE, Gregorian in 1582.
Current use: Age calculation, Contract terms, Historical events
Decade (decade)
A decade is 10 years. Used for describing periods and trends.
Origin: From Greek deka for ten. Common in statistical and cultural references.
Current use: Trend analysis, Historical periods, Technology cycles
Century (century)
A century is 100 years. Used for historical periods and ages.
Origin: From Latin centuria, a group of 100. Used to divide history into periods.
Current use: Historical periods, Age designations, Long-term planning
Millennium (millennium)
A millennium is 1000 years. Used for major historical and religious periods.
Origin: From Latin mille (thousand). Calendars often mark millennium transitions.
Current use: Historical periods, Religious observances, Long-term projections
Sidereal Day (sidereal d)
Time for Earth to rotate relative to stars ≈ 23h 56m.
Origin: Used in astronomy.
Current use: Astronomy, Satellite operations
Julian Year (Julian yr)
Exactly 365.25 days = 31,557,600 seconds.
Origin: Astronomical standard.
Current use: Astronomy, Light-year calculation
Common uses for time conversions
Time conversions are used in scheduling, project management, payroll, sports timing, cooking, astronomy, history, and scientific experiments.
Frequently asked questions about time
How many seconds are in 1 hour?+
There are 3,600 seconds in 1 hour.
How many days are in a year?+
A common year has 365 days. A leap year has 366 days. For conversions, a standard year is often approximated as 365.25 days.
Which time units does this converter support?+
It supports metric and everyday units from nanoseconds to millennia, plus astronomical time units — over 15 in total.