Speed Calculator
Please provide any two values in the fields below to calculate the third value in the speed distance time equation:
| speed = | distance |
| time |
Speed Converter
The following converter converts between common units of speed.
Speed, distance, and time
What is speed?
Speed describes how quickly an object's position changes over time. In other words, it measures the rate at which something travels a certain distance. In the International System of Units (SI) the standard unit is metres per second (m\/s), though kilometres per hour (km\/h), miles per hour (mph), feet per second (ft\/s) and other units are also used. The choice of unit depends on the measurement system of a country and on what is being measured. For example, reporting a snail’s crawl in metres per second would be impractical because the values are tiny, while expressing a race‑car’s velocity in millimetres per second would produce unnecessarily large numbers.
The relationship between speed, distance, and time
Speed, distance, and time are related by the following formula:
| speed = | distance |
| time |
This formula shows that:
Example:
Suppose you pedal a bicycle at a constant speed of 10 metres per second (m\/s) for exactly one minute. How far will you have traveled by the end of that minute?
First, convert the minute into seconds because the speed is expressed per second. One minute equals 60 seconds. Then apply the distance equation:
| distance = | speed × time |
| = | 10 m/s × 60 s |
| = | 600 m |
This means you will have traveled 600 meters in one minute.
Understanding how speed, distance, and time relate to each other isn’t just academic; it’s useful in everyday life. Whether you’re estimating how long it will take to reach school at a certain speed, figuring out the pace needed to win a race, or learning why road speed limits are set for safety, these concepts are extremely practical.
Common units of speed
| m/s | km/h | mph | kn | ft/s | |
|---|---|---|---|---|---|
| 1 meter/second [m/s] = | 1 | 3.6 | 2.236928 | 1.943844 | 3.280840 |
| 1 kilometer/hour [km/h] = | 0.277778 | 1 | 0.621369 | 0.539957 | 0.911344 |
| 1 mile/hour [mph] = | 0.44704 | 1.60935 | 1 | 0.868979 | 1.466672 |
| 1 knot [kn] = | 0.514444 | 1.852 | 1.150775 | 1 | 1.687810 |
| 1 foot/second [ft/s] = | 0.3048 | 1.09728 | 0.681816 | 0.592484 | 1 |
Examples of different speeds
| m/s | km/h | mph | |
|---|---|---|---|
| Average walking speed | 1.4 | 5 | 3.1 |
| Peak human running speed | 12.42 | 44.7 | 27.8 |
| Peak cheetah running speed | 33.53 | 120.7 | 75 |
| Average orbital speed of the Earth | 29,783 | 107,218 | 66,623 |
| Average orbital speed of the Sun | 251,000 | 904,000 | 561,000 |
| Speed of sound in air (sea level, 20°C) | 343 | 1,235 | 768 |
| Speed of light in vacuum | 299,792,458 | 1,079,252,848 | 670,616,629 |