What Is Grid in Matplotlib?

A grid in Matplotlib is a set of horizontal and vertical lines displayed on a chart to make data easier to read and interpret.
Grid lines help viewers compare values, align points with axes, and understand scale clearly.

Grids are commonly used in line charts, bar charts, and scatter plots.

Basic Grid Example

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4] y = [10, 20, 15, 25] plt.plot(x, y) plt.grid() plt.show() # Output: # Line chart with default grid lines

Turning Grid On or Off

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4] y = [10, 20, 15, 25] plt.plot(x, y) plt.grid(True) # Turn ON plt.grid(False) # Turn OFF plt.show() # Output: # Grid enabled or disabled

Changing Grid Line Style

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4] y = [10, 20, 15, 25] plt.plot(x, y) plt.grid(linestyle="--") plt.show() # Output: # Chart with dashed grid lines

Common Line Styles

StyleDescription
"-"Solid line
"--"Dashed line
":"Dotted line
"-."Dash-dot line

Changing Grid Color and Width

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4] y = [10, 20, 15, 25] plt.plot(x, y) plt.grid(color="gray", linewidth=1) plt.show() # Output: # Gray grid lines with custom thickness

Grid for Specific Axis

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4] y = [10, 20, 15, 25] plt.plot(x, y) plt.grid(axis="x") # Only vertical grid plt.show() # Output: # Grid lines only on X-axis

Combining Customizations

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4] y = [10, 20, 15, 25] plt.plot(x, y) plt.grid(color="blue", linestyle=":", linewidth=0.8) plt.show() # Output: # Blue dotted grid lines

Why Use Grid Lines?

  • Improve data readability

  • Help align data points

  • Enhance presentation quality

  • Useful for precise comparison of values