# What is Length? (With Definition, Unit & Conversion)

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When you see objects like trees, buildings, bridges, roads, etc., what type of measurement comes to your mind? Obviously the height or the length, or the breadth. Height and breadth are also a form of length.

Measuring length means measurement of the size such as the height of any object, or distance from one to another with the help of measuring tools like a ruler, measuring tape, etc. For example, the height of trees, buildings, and bridges can be measured in metres, the length of a road can be measured in kilometres, and the length of a notebook and pencil can be measured in inches using a ruler, etc.

Let’s learn what is length and its measurement and units in detail.

## What is Length?

Length is the term used for identifying the size of an object or distance from one point to the other. Length can be defined as the measurement or extent of something from end to end. The length helps you in identifying a larger or a smaller of two or more objects.

For example, the length of a notebook tells you how long the notebook is.

## What is Measurement of Length?

Measurement of length can be defined as a process of identifying the length of objects in some standard or non-standard units. Knowledge of measuring the length of an object is one of the basic skills you need in everyday life.

You can measure the length of an object by using different units like metre, centimetre, feet, an inch, or by using a handspan, foot span, etc. There are broadly two types of units that people around the world use.

• Non-Standard Units of Measuring Length
• Standard Units of Measuring Length

### Non-Standard Units of Measuring Length

Handspan: Handspan is the maximum distance between the tips of the thumb and the little finger. It is generally about $8$ inches, but it depends on your hand.

Foot span: The foot span is defined as the distance between the point of the toe and the heel of the foot. This again may vary from person to person.

Cubit:  The cubit is defined as the length of the forearm from the elbow to the tip of the middle finger. This unit of measurement is different for different people.

### Standard Units of Measuring Length

Standard units are predefined and are based on some fixed or standardized. These units do not change from person to person or object to object. Suppose, there are two people measuring the length of a pencil with a ruler. If they use the standard units, they will get the same value.  Some examples of measurement of length using standard units are centimetre, metre, kilometre, inch, feet, yard, etc.

The standard units of measuring length are broadly divided into two types.

• Metric System of Length
• Imperial System oF Length

#### Metric System of Length

The metric system includes kilometre, hectometre, decametre, metre, decimetre, centimetre, and millimetre. There is a relationship between these units. The base unit is a metre.

The units used in the metric system are given below:

The relationship of every other unit with the base unit (meters) is given below:

#### Imperial System of Length

The imperial system includes feet, yard, inches, etc. The relation is given by:

The conversion from the metric system to the imperial system is given by:

The conversion from the imperial system to the metric system is given by:

#### S.I. Unit of Length

The S.I. unit is an international system of measurements that is used universally in technical and scientific research to avoid confusion with the units. The S.I unit to measure the length is given in metre (m). The metre is the base unit of length.

## How to Measure Length?

There are two sides of a ruler. On one side, we see centimeters/millimeters and on the other side, we see inches. The following steps are required to measure the length of an object:

Step 1: Choose the unit in which you want to measure the length of an object. If you want a value in cm/mm, then use the cm/mm side of the ruler. If you want the value in inches, then use the inches side of the ruler.

Step 2: Find the $0$ mark on one end of the ruler. Align the zero mark with the starting edge of the object to be measured.

Step 3: Look at the endpoint of the object and note the value. For example, in the below figure, the length of the pencil is from $0$ to $14$ cm.

## Conclusion

Length is the measurement or extent of something from end to end. To measure length we use three different types of systems, viz, metric system, imperial system, and S.I. system. In the olden days, people used non-standard units such as hand span, leg span, cubit, etc.

## Practice Problems

Convert the following

• $12$ m to cm
• $156$ cm to m
• $120$ dm to m
• $8$ feet to m
• $12$ m to feet
• $14$ m to inch
• $128$ inch to feet

## FAQs

### What is measuring length?

Measurement of length can be defined as a process of identifying the length of objects in some standard or non-standard units.

### What is the SI unit of measurement of length?

The SI unit of measurement of length is metre.

### What is the unit of measurement of length?

The unit of measurement of length is metre.

### What are the instruments for measuring length?

There are various instruments or tools for measuring length such as a ruler, yardstick, meter stick, feet scale, measuring tape, etc.

### What are the non-standard units of measuring length?

There are many non-standard units of measuring length. The most common of them are handspan, foot span, and cubit.