Available Time units

• second conversions

  The second is the SI base unit of time. It is used globally in science, engineering, computing, and everyday life, and is the foundation upon which all other time units are built.

• minute conversions

  A minute is a unit of time equal to 60 seconds. It is universally used for scheduling, cooking, fitness tracking, and expressing short durations in everyday life.

• hour conversions

  An hour is a unit of time equal to 60 minutes. It is the standard unit for time-of-day references, work schedules, travel durations, and billing periods across most global contexts.

• day conversions

  A day is a unit of time equal to 24 hours, corresponding to one full rotation of the Earth. It is the primary unit for calendars, deadlines, event scheduling, and date-based calculations.

• week conversions

  A week is a unit of time equal to 7 days. It is the standard cycle for work schedules, recurring events, sports seasons, and planning in most cultures worldwide.

• year (365 d) conversions

  A year is a unit of time equal to 365 days, representing approximately one orbit of the Earth around the Sun. It is used for long-term planning, age calculation, financial cycles, and historical timekeeping.

• millisecond conversions

  A millisecond is a unit of time equal to one thousandth of a second. It is used in computing, networking, audio and video processing, and measuring reaction times and signal latencies.

• microsecond conversions

  A microsecond is a unit of time equal to one millionth of a second. It is used in electronics, radar systems, telecommunications, and measuring the speed of high-frequency processes.

• nanosecond conversions

  A nanosecond is a unit of time equal to one billionth of a second. It is critical in computer processor timing, high-frequency trading, optical communications, and physics experiments.

• century (100 yr) conversions

  A century is a unit of time equal to 100 years. It is used in historical analysis, long-term demographic and climate projections, and describing spans of civilizational or geological time.

Assumption: year is defined as 365 days and century values are approximate.

Full Time conversion matrix

About Time

Units of time

Real-world uses

Time measurement governs everything from coordinating international flights to synchronising financial transactions that settle in microseconds. GPS satellites rely on atomic clocks accurate to billionths of a second to calculate position. In medicine, heart rate and drug half-lives are timed precisely. Sports record performances to the hundredth of a second. Even everyday cooking depends on accurate timing, and global telecommunications networks require nanosecond-level synchronisation to function.

History

The Babylonians gave us the 60-minute hour and 60-second minute around 2000 BCE, using their base-60 numeral system. Sundials and water clocks were the primary timekeeping devices for millennia. Mechanical clocks appeared in 13th-century Europe, and the pendulum clock, invented by Christiaan Huygens in 1656, brought accuracy to within seconds per day. In 1967, the SI second was redefined based on caesium-133 atomic transitions, achieving accuracy of one second in 300 million years.

Common mistakes

A common error is confusing a 12-hour clock with a 24-hour clock, especially across time zones — "12 AM" is midnight, not noon. People often mistake a calendar year (365 or 366 days) for a Julian year (exactly 365.25 days) used in astronomy. Another frequent mistake is assuming all time zones differ by whole hours; several, like India (UTC+5:30) and Nepal (UTC+5:45), use fractional offsets.

Measurement standards

The SI second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium-133 atom, maintained by the BIPM and national metrology institutes worldwide.

Did you know?

Earth's rotation is gradually slowing due to tidal friction with the Moon. To keep atomic time aligned with solar time, "leap seconds" have been inserted 27 times since 1972 — though they are scheduled to be abolished by 2035.

Common values