What is second?

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.

Real-world uses

The second is the SI base unit of time, fundamental to all scientific measurement, computing clock cycles, athletic timing, and GPS satellite synchronization. Everyday timekeeping, cooking timers, and traffic light cycles all rely on seconds.

History

The concept of dividing the day into 86,400 parts dates to ancient Babylonian and Egyptian timekeeping. Since 1967, the SI second has been defined as 9,192,631,770 periods of the radiation from a caesium-133 atom.

Common mistakes

Assuming a second has always been 1/86,400 of a day. The modern SI second is defined by caesium atom vibrations and is independent of Earth's rotation, which varies slightly due to tidal friction.

What is millisecond?

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.

Real-world uses

Milliseconds are critical in computing for measuring network latency (ping times), database query performance, and real-time system response. Financial trading platforms measure order execution in milliseconds, and human reaction time averages about 250 ms.

History

The millisecond became a practical unit with the invention of precise mechanical chronographs in the 19th century. Its importance exploded with electronic computing, where operations occur in millisecond and sub-millisecond timescales.

Common mistakes

Confusing milliseconds with microseconds in performance profiling—they differ by a factor of 1,000. Also, assuming human perception cannot detect millisecond differences, when in fact audio delays above 10 ms are perceptible.

When is this conversion used?

Converting second to millisecond is useful in the time domain when comparing values across different measurement standards or applying formulas that require a specific unit.

Worked examples

1 second = 1,000 millisecond

1 millisecond = 0.001 second

How to convert second to millisecond

To convert second to millisecond, multiply the value by 1,000.

To convert millisecond back to second, multiply by 0.001.

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.

Quick reference: second to millisecond

secondmillisecond
0.1100
0.5500
11,000
22,000
55,000
1010,000
2525,000
5050,000
100100,000
250250,000
500500,000
1,0001,000,000

Common values

secondmillisecond
Blink of an eye0.3 second300 millisecond
Average pop song210 second210,000 millisecond
Feature film7,200 second7,200,000 millisecond
One work day (8 hrs)28,800 second28,800,000 millisecond
One calendar year31,536,000 second3.153600e+10 millisecond