Speed of Light Calculator
Table of contents
What is the speed of light? How fast is the speed of light?How to calculate the speed of light?FAQsWith this speed of light calculator, we aim to help you calculate the distance light can travel in a fixed time. As the speed of light is the fastest speed in the universe, it would be fascinating to know just how far it can travel in a short amount of time.
We have written this article to help you understand what the speed of light is, how fast the speed of light is, and how to calculate the speed of light. We will also demonstrate some examples to help you understand the computation of the speed of light.
What is the speed of light? How fast is the speed of light?
The speed of light is scientifically proven to be the universe's maximum speed. This means no matter how hard you try, you can never exceed this speed in this universe. Hence, there are also some theories on getting into another universe by breaking this limit. You can understand this more using our speed calculator and distance calculator.
So, how fast is the speed of light? The speed of light is 299,792,458 m/s in a vacuum. The speed of light in mph is 670,616,629 mph. With this speed, one can go around the globe more than 400,000 times in a minute!
One thing to note is that the speed of light slows down when it goes through different mediums. Light travels faster in air than in water, for instance. This phenomenon causes the refraction of light.
Now, let's look at how to calculate the speed of light.
How to calculate the speed of light?
As the speed of light is constant, calculating the speed of light usually falls on calculating the distance that light can travel in a certain time period. Hence, let's have a look at the following example:
 Source: Light
 Speed of light: 299,792,458 m/s
 Time traveled: 100 seconds
You can perform the calculation in three steps:

Determine the speed of light.
As mentioned, the speed of light is the fastest speed in the universe, and it is always a constant in a vacuum. Hence, the
speed of light
is299,792,458 m/s
. 
Determine the time that the light has traveled.
The next step is to know how much time the light has traveled. Unlike looking at the speed of a sports car or a train, the speed of light is extremely fast, so the time interval that we look at is usually measured in seconds instead of minutes and hours. You can use our time lapse calculator to help you with this calculation.
For this example, the
time
that the light has traveled is100 seconds
. 
Calculate the distance that the light has traveled.
The final step is to calculate the total distance that the light has traveled within the
time
. You can calculate this answer using the speed of light formula:distance = speed of light × time
Thus, the
distance
that the light can travel in100 seconds
is299,792,458 m/s × 100 seconds = 29,979,245,800 m
What is the speed of light in mph when it is in a vacuum?
The speed of light in a vacuum is 670,616,629
mph. This is equivalent to 299,792,458
m/s or 1,079,252,849
km/h. This is the fastest speed in the universe.
Is the speed of light always constant?
Yes, the speed of light is always constant for a given medium. The speed of light changes when going through different mediums. For example, light travels slower in water than in air.
How can I calculate the speed of light?
You can calculate the speed of light in three steps:

Determine the time that the light has traveled.

Determine the distance the light has traveled.

Apply the speed of light formula:
speed of light = distance / time
How far can the speed of light travel in 1 minute?
Light can travel 17,987,547,480 m
in 1 minute. This means that light can travel around the earth more than 448
times in a minute.