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Unit of Distance – SI Unit

Last Updated : 19 Mar, 2024
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Unit of Distance is meter denoted as ‘m’. Distance is a fundamental concept in physics and everyday life, quantifies the length of path between two points or objects. The other common units of distance are kilometer(km), centimeter(cm), yard(yd), inch(in), miles(mi), etc.

In this article, we will learn about the definition of distance, unit of distance across different systems, conversion of unit of distance, and some solved examples based on it.


Definition of Distance

Distance can be defined as the total movement of a body from one point to another point. It is the measure of how far or how close one object is to the other object.

Distance is the total length of path covered from one point to another by an object.

Mathematically, we can say the distance is the product of the velocity of a body moving between two points with the time taken to move between those two points.

Unit Of Distance

Unit of distance refers to the standard quantity use to measure the extent of space between two objects or points. Even every quantity is physics is linked with some units to define it properly and to avoid confusion.

There are various units of distance available like- Metric system ,Imperial System Nautical system etc.

The SI unit of Distance is meter. Other units of distance include cm, yard, inch, miles, kilometer(km), etc.

Distance Formula

To calculate the distance between two objects or places following formula is used:

We know that,

Speed = Distance / Time

Therefore using the above formula we get the formula for the distance when the speed and time of any motion is given is,

Distance = Speed × Time

d = s × t


  • d is the Distance Covered Object
  • s is the Speed
  • t is the Time Taken

SI Unit Of Distance

There are several units of distance available in different unit system but the Standard International (SI) unit of distance is meters. Meter is also use to measure length of any object. It is accepted universally to measure distance and length in scientific contexts and daily life.

SI Unit of distance is meter.

Note: The other units of distance include kilometer, centimeter, millimeter, etc.

Unit of Distance in Other Systems

The unit of distance in other systems are given below:

  • Metric System
  • Imperial System (British/American)
  • CGS System

Metric System

The different units of distance in metric system are given below:

  • Millimeter (mm)
  • Centimeter (cm)
  • Decimeter (dm)
  • Meter (m)
  • Decameter (dam)
  • Hectometer (hm)
  • Kilometer (km)

Imperial System (British/American)

The distance units used in Imperial system are:

  • Inch (in)
  • Foot (ft)
  • Yard (yd)
  • Mile (mi)

CGS System of Unit of Distance

The CGS (centimeter-gram-second) unit of distance is the centimeter (cm). In the CGS system, distance is typically measured in centimeters.

Other Units of Distance

  • Angstrom (Å) – used in physics and chemistry to measure atomic and molecular distances.
  • Fermi (fm) – used in nuclear physics to measure atomic distances.
  • Nautical Units: 1 nautical mile (nmi) = 1852 meters (m)

Conversion Between Units of Distance

Below are the conversion table of different units of distance:

Metric System

The conversion table of unit of distance in metric system is given below:


Equivalent Unit (in m)

1 millimeter (mm)

0.001 meters

1 centimeter (cm)

0.01 meters

1 decimeter (dm)

0.1 meters

1 decameter (dam)

10 meters

1 hectometer (hm)

100 meters

1 kilometer (km)

1000 meters

Imperial System (British/American)

The equivalent value (in meters) of units of distance in imperial system is given below:


Equivalent Unit (in m)

1 inch (in)

0.0254 meters

1 foot (ft)

0.3048 meters

1 yard (yd)

0.9144 meters

1 mile (mi)

1609.34 meters

Other Units of Distance

  • 1 angstrom (Å) = 1 × 10-10 meters (m)
  • 1 fermi (fm) = 1 × 10-15 meters (m)
  • 1 nautical mile (nmi) = 1852 meters (m)

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Solved Examples Based On Distance Unit

Example 1: Amy is planning a road trip from City A to City B. The total time taken to travel between City A and City B is 5 hours. If Amy drives at an average speed of 60 miles per hour, how much distance she traveled to reach City B?


To find the distance traveled by Amy to reach City B, we can use the formula:

Distance= speed × time


Time = 5 hours

Speed = 60 miles per hour

Substituting the values into the formula:

distance = 60 × 5

distance = 300 miles

Therefore, Amy traveled 300 miles to reach City B.

Example 2: John is jogging around a circular track of 250 meters. Find the distance covered by him if he takes 6 laps of the track (in km).


Distance John runs in 6 laps can be given by:

Total distance = 250 × 6 = 1500 meters

We know, 1 kilometer = 1000 meter

Therefore, 1500 meter = 1500/1000 km = 1.5 km

Therefore, John runs 1.5 kilometers in 6 laps around the circular track.

Practice Questions on Distance Unit

Question 1: John walks 2 kilometers to reach his friend’s house. He then walks back home using the same route. How many kilometers does John walk in total?

Question 2: A car travels at a speed of 60 kilometers per hour for 3 hours. How far does the car travel in total?

Question 3: Sara’s house is 15 meters away from the bus stop. If she walks to the bus stop and then returns home, what is the total distance she walks?

Question 4: A plane flies at an average speed of 800 kilometers per hour. How far can it travel in 5 hours?

Question 5: A swimming pool is 25 meters long. If Tom swims the length of the pool 10 times, how many kilometers does he swim in total?.

Unit of Distance: Frequently Asked Questions

What is distance?

It can be defined as the total movement of a body from one point to another point

What is the formula for distance?

The Distance is given as speed multiplied to time:

D= S×T


  • D is the distance,
  • S is speed and,
  • T is time.

How do we measure distance on maps?

On maps, distance is typically measured using a scale. A scale represents the ratio between a unit of length on the map and the corresponding distance on the ground. For example, 1 inch on the map might represent 1 mile in reality.

What is a common unit for measuring short distances?

For short distances, common units of measurement include centimeters (cm) and millimeters (mm). These units are suitable for measuring small objects or distances.

What is the difference between distance and length?

Distance refers to the extent of space between two points, while length usually denotes the size of an object in one dimension. Length is a property of an object, while distance is the measure between two objects or points.

How many centimeters is equal to one meter?

100 cm is equal to 1 meter.

What are the common units of distance?

The common units of distance are: meter (m), Kilometer (km), centimeters (cm), millimeters (mm), etc.

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