How to Use Bold Font in Matplotlib (With Examples)


You can use the weight argument to create a bold font in Matplotlib.

This argument is commonly used with titles and annotated text in Matplotlib:

Method 1: Use Bold Font in Title

plt.title('My Title', weight='bold')

Method 2: Use Bold Font in Annotated Text

plt.text(6, 10, 'some text', weight='bold')

The following examples show how to use each method in practice.

Example 1: Use Bold Font in Title

The following code shows how to create a scatterplot with a title in Matplotlib that uses regular font:

import matplotlib.pyplot as plt

#create data
x = [3, 6, 8, 12, 14]
y = [4, 9, 14, 12, 9]

#create scatterplot
plt.scatter(x, y)

#add title
plt.title('My Title', fontsize=22)

And the following code shows how to create a scatterplot with a title in Matplotlib and use the weight argument to enable bold font:

import matplotlib.pyplot as plt

#create data
x = [3, 6, 8, 12, 14]
y = [4, 9, 14, 12, 9]

#create scatterplot
plt.scatter(x, y)

#add title
plt.title('My Title', fontsize=22, weight='bold')

Matplotlib bold font in title

Example 2: Use Bold Font in Annotated Text

The following code shows how to use the weight argument to enable bold font in an annotated text in a Matplotlib scatterplot:

import matplotlib.pyplot as plt

#create data
x = [3, 6, 8, 12, 14]
y = [4, 9, 14, 12, 9]

#create scatterplot
plt.scatter(x, y)

#add regular text
plt.text(6, 10, 'Normal Font',  fontsize=16)

#add bold text
plt.text(10, 10, 'Bold Font', fontsize=16, weight='bold')

Matplotlib bold font in annotated text

Notice the difference between the normal font and the bold font.

Additional Resources

The following tutorials explain how to perform other common tasks in Matplotlib:

How to Add Legend to Scatterplot in Matplotlib
How to Color a Scatterplot by Value in Matplotlib
How to Add an Average Line to Plots in Matplotlib

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