Horizontal Bar Graph – Definition, Types, Parts, Examples

What is a Horizontal Bar Graph?

A horizontal bar graph displays the information using horizontal bars. It helps us to visualize and compare data for different categories.

A bar graph is a graph with rectangular bars with lengths and heights proportional to the values that they represent. The advantage of bar graphs is they are easy to read and understand. They instantly give you an idea about the given data set.

Horizontal bar graphs represent the data horizontally. These are sideways bar graphs whose bars are drawn horizontally.

Parts of a Horizontal Bar Graph

A horizontal bar graph is a bar graph drawn with rectangular bars of lengths proportional to the values that they represent. 

• On the y-axis of the graph, it shows the data categories that are being compared.
• The x-axis represents the values corresponding to each data category.

Let’s see examples of horizontal bar graphs to understand this.

Example 1: A horizontal bar graph of the favorite color of 50 students is shown below. On the y-axis, you can see the data categories (different colors). On the x-axis, you can see the data values (number of students).

Example 2: In the given horizontal bar graph, we can infer that 1 unit represents 5 students on the scale. We can see that 10 students like red, 5 like yellow, 20 like blue, and 15 like green.

The data categories are shown on the vertical axis, while the values or frequencies are represented on the horizontal axis. The length of each bar is equal to the value corresponding to the data category, and all bars go across from left to right horizontally on a graph.

For example, in the graph below, the vertical axis shows us the seasons, and the horizontal axis shows us the temperature data for each season.

The horizontal axis represents the numerical values, while the vertical axis represents different categories.

Scale of Horizontal Bar Graphs

The scale of a bar graph describes the relation between the unit length of the bar and the quantity it represents. The scale makes it easier to measure or quantify the given data. 

For example: If the scale of a bar graph is 1 unit = 5 objects, then the bar having 2 units length represents 10 objects. This way, you don’t have to draw a 10 unit long bar to represent 10 objects.

Drawing Horizontal Bar Graphs

How do we draw or plot horizontal bar graphs? Let’s understand it.

Step 1: Draw the two axes of the graph—the vertical X-axis and the horizontal Y-axis.

Step 2: The category that has to be compared is represented on the Y-axis. The measure or quantity is represented by the X-axis.

Step 3: To draw the horizontal bar, plot the vertical X-axis and then the horizontal Y-axis up to the length that is proportional to the value.

Step 4: If there is more than one parameter for each category, you can use different colors. 

Step 5: Add the category labels and title the graph. Give a scale for the graph. 

Here is the data showing the number of children who visited a library during the first three months of a year.

To represent this data on a horizontal bar graph, use following steps:

So, taking a scale of 10, we get the graph as:

What Are the Types of Horizontal Bar Graphs?

The types of horizontal bar graphs are as follows:

1. Simple Horizontal Bar Graphs

In simple horizontal bar graphs, the categories are compared based on a single parameter. For example, you can compare the rainfall in different cities. However, you cannot compare the rainfall and the sunshine in different cities. 

2. Double Horizontal Bar Graphs

In double horizontal bar graphs, you can compare different categories based on two parameters. For example, you can compare rainfall and sunshine in different cities. 

3. Multiple Horizontal Bar Graphs

In multiple horizontal bar graphs, you can compare categories based on various parameters. For example, you can compare rainfall, sunshine, temperatures, and humidity across different cities.

The Benefits of Horizontal Bar Graphs

The benefits of horizontal bar graphs are that the categories are easier to view when you look at the chart. These bar graphs are also easier to view on smaller devices like phones. 

Further, it is also easier to visualize and compare the data based on the bar length and the bar color. For example, in a graph about pollutant levels, the measure of a pollutant can be indicated by the length of the bars. The color of the bar can indicate whether the pollutant levels are hazardous or not. 

Are Vertical or Horizontal Bar Graphs Better?

Vertical bar graph advantages include scope for longer bars since there is more space for them to fit on the page.

Horizontal bar graphs tend to be better for data with fewer categories or where the items being compared are very important. 

What Are the Other Types of Bar Charts?

The other types of bar charts are:

• Stacked bar graphs
• Clustered bar graphs
• Percentage bar diagrams

Facts about Horizontal Bar Graph

The x-axis and the y-axis are switched in a vertical bar graph.

Conclusion

A horizontal bar graph helps us visualize and compare data for different categories or items. It brings the categories into focus and helps us visualize data with bars of different sizes and colors. 

Solved Examples On Horizontal Bar Graph

1. The data of the number of visitors to a museum for four months is shown below. Draw a horizontal bar graph to display the same. Also, what type of horizontal bar graph would you draw? 

Solution: 

Since there is only one parameter (number of visitors), we would draw a simple bar graph. 

We can choose the scale as 1 unit $= 50$ people

2. You want to compare different subjects based on the number of students who have taken the subject and the number of students who like the subject. What type of horizontal bar chart would you draw? 

Solution:

We are comparing subjects based on two parameters.

1. Number of students who have taken the subject. 
2. Number of students who like the subject.

Thus, we will draw a double horizontal bar chart. 

3. If you want to compare different types of notebooks based on 1) the number of lines per page, 2) the number of pages, and 3) the number of sections, what type of horizontal bar graph would you draw?

Solution:

Since we are comparing the types of notebooks based on multiple parameters (the number of lines per page, the number of pages, and the number of sections), we would draw a multiple horizontal bar chart.

4. Based on the given horizontal bar chart, how many people in the survey wear medium-sized T-shirts? What is the scale?

Solution: 

The scale is 1 unit $= 10$ people

The length of the bar corresponding to the medium size reads 20.

The number of people wearing medium size $= 20$.

5. In a class, 10 students play basketball, 15 students play football, and 5 students play tennis. Draw a horizontal bar chart to show this information.

Solution:

The number of students that play basketball $= 10$

The number of students that play football $= 15$

The number of students that play tennis $= 5$

Choose scale as 1 unit $= 5$ students

Practice Problems On Horizontal Bar Graph

Frequently Asked Questions On Horizontal Bar Graph