How to Set Figure Size in Matplotlib: Simple Guide

To set the figure size in Matplotlib, use the figsize parameter inside plt.figure() or plt.subplots(). The figsize takes a tuple of width and height in inches, for example, figsize=(8, 6) sets the figure width to 8 inches and height to 6 inches.

Syntax

The figsize parameter controls the size of the figure in inches. It is used as a tuple (width, height) where both values are numbers representing inches.

You can set it when creating a figure with plt.figure(figsize=(width, height)) or when creating subplots with plt.subplots(figsize=(width, height)).

python

import matplotlib.pyplot as plt

plt.figure(figsize=(width, height))  # width and height are floats or ints in inches

# or
fig, ax = plt.subplots(figsize=(width, height))

Example

This example shows how to create a plot with a figure size of 8 inches wide and 4 inches tall. The plot will display a simple line graph.

python

import matplotlib.pyplot as plt

plt.figure(figsize=(8, 4))
plt.plot([1, 2, 3, 4], [10, 20, 25, 30])
plt.title('Line Plot with Custom Figure Size')
plt.xlabel('X axis')
plt.ylabel('Y axis')
plt.show()

Output

A plot window opens showing a line graph with a wide rectangular shape (8x4 inches).

Common Pitfalls

• Not using figsize inside the figure creation function causes the default size to be used, which might be too small or large.
• Passing figsize as a single number or wrong type instead of a tuple will cause errors.
• Changing figure size after plotting without recreating the figure does not resize the plot.

python

import matplotlib.pyplot as plt

# Wrong: figsize as single number (causes error)
# plt.figure(figsize=8)  # This will raise a TypeError

# Correct way:
plt.figure(figsize=(8, 6))
plt.plot([1, 2, 3], [4, 5, 6])
plt.show()

Output

A plot window opens with a figure sized 8x6 inches.

Quick Reference

Use this quick guide to remember how to set figure size in Matplotlib:

Action	Code Example	Description
Create figure with size	plt.figure(figsize=(width, height))	Sets figure size in inches when creating a figure
Create subplots with size	fig, ax = plt.subplots(figsize=(width, height))	Sets figure size for subplots
Width and height units	figsize=(8, 6)	Width and height are in inches
Common mistake	plt.figure(figsize=8)	Wrong: figsize must be a tuple

Key Takeaways

Set figure size using the figsize parameter as a tuple (width, height) in inches.

Use figsize inside plt.figure() or plt.subplots() when creating the plot.

Always pass figsize as a tuple, not a single number.

Changing figure size after plotting requires creating a new figure.

Proper figure size helps make plots clear and readable.