# What Is a Microsecond?

K'Lee Banks

Most people understand how units of time can be broken down into smaller units. For example, an hour breaks down into 60 minutes, and a minute further breaks down into 60 seconds. Even smaller units exist, however, and are represented as fractions of seconds — including the microsecond, which is one millionth of a second. In addition to the microsecond, some of these other smaller units include a nanosecond and a millisecond.

Generally used in scientific and engineering applications, one microsecond is equivalent to one millionth of a second. In other words, if a second was divided into one million equal parts, each individual part would be what is known as the microsecond. This may sometimes cause confusion because of the fact that another sub-second measurement of time is known as the millisecond. The difference between the microsecond and the millisecond is that the latter is only one one-thousandth of a second, rather than the microsecond's one millionth of a second measure.

Specially designed websites can convert seconds into microseconds, or vice versa. Most of the general public has no use for such small units of measurement, but should the need arise, one only has to search online for a microsecond converter or the formula for units of time conversion rates. While most individuals will never have a need or use for such conversion, other than to grasp the concept of such small units of time, professionals involved in science or engineering may in fact benefit from such knowledge.

An example that most people can relate to may help to explain just how short these units of time actually are. It is common knowledge that blinking takes virtually no time at all. The average time required for one eye blink, however, is approximately 350,000 microseconds! Another example, yet slightly shorter in time span, is a standard camera flash. A flash that people see in an instant is actually 1,000 microseconds long, or one millisecond.

Common uses for these ultra small units of time are evident in radio broadcast frequencies, or other audible sounds or tones. For example, the cycle time for the frequency 100 kHz is 100 microseconds. Additionally, the highest frequency audible to the human ear is 20 kHz, and only takes 50 microseconds. Still other uses for the microsecond tend to be more complex, such as those used in astronomical calculations, physics, and chemistry.