What is The Smallest Unit Of Time?

what is the smallest unit of time
Source: Thrive Global

If anybody asks us what is the largest unit of time to measure, then the first thing that comes to everyone’s mind is, light year. Light is the fastest thing in the world, and light year means how many years will light take to reach any place. A light-year is generally used to measure the distance to reach other planets, satellites, etc. outside the Earth. We all know about a light-year, that this is the highest unit to measure time but do you know, what is the smallest unit to measure time? I know most of us don’t so let’s find out what is the smallest unit of time…

The smallest measure of time comes from a unit of distance, which is called the length of Planck. This is where the dimensions become so small that the classical rules of physics are broken and the quantum is in effect. It is the time which takes by light to travel Planck’s length.

Since the distance/relativity stops at the length of Planck and quantum mechanics works, so the lengths that are less than this limit are redundant. As I mentioned the fastest thing in the universe right now is light, So if we take the shortest length(plank’s length), and divide it by the fastest speed which is speed of light, then we will be able to find out how much time the fastest thing takes to reach the shortest distance.

So the smallest unit of time is known as Planck’s time, which is about 3.3 × 10-44 seconds. The Planck’s length is about 1 x 10-34 m and the Speed of light is about 3 x 108 m/second.

Read Also: Is zero an even number, or an odd number?

So hopefully, now you know what is the smallest unit of time and in future, if anyone asks you about it you can explain him easily. But still, if you have any questions regarding the highest and the smallest measurement of time, so you can ask us in the comments section.


  1. A light-year is a unit of distance, not time. A light-year is how astronomers measure distance in space. It’s defined by how far a beam of light travels in one year – a distance of six trillion miles.


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