How to change the font size on a matplotlib plot

From the matplotlib documentation,

font = {'family' : 'normal',        'weight' : 'bold',        'size'   : 22}matplotlib.rc('font', **font)

This sets the font of all items to the font specified by the kwargs object, font.

Alternatively, you could also use the rcParams update method as suggested in this answer:

matplotlib.rcParams.update({'font.size': 22})

or

import matplotlib.pyplot as pltplt.rcParams.update({'font.size': 22})

You can find a full list of available properties on the Customizing matplotlib page.

If you are a control freak like me, you may want to explicitly set all your font sizes:

import matplotlib.pyplot as pltSMALL_SIZE = 8MEDIUM_SIZE = 10BIGGER_SIZE = 12plt.rc('font', size=SMALL_SIZE)          # controls default text sizesplt.rc('axes', titlesize=SMALL_SIZE)     # fontsize of the axes titleplt.rc('axes', labelsize=MEDIUM_SIZE)    # fontsize of the x and y labelsplt.rc('xtick', labelsize=SMALL_SIZE)    # fontsize of the tick labelsplt.rc('ytick', labelsize=SMALL_SIZE)    # fontsize of the tick labelsplt.rc('legend', fontsize=SMALL_SIZE)    # legend fontsizeplt.rc('figure', titlesize=BIGGER_SIZE)  # fontsize of the figure title

Note that you can also set the sizes calling the rc method on matplotlib:

import matplotlibSMALL_SIZE = 8matplotlib.rc('font', size=SMALL_SIZE)matplotlib.rc('axes', titlesize=SMALL_SIZE)# and so on ...

If you want to change the fontsize for just a specific plot that has already been created, try this:

import matplotlib.pyplot as pltax = plt.subplot(111, xlabel='x', ylabel='y', title='title')for item in ([ax.title, ax.xaxis.label, ax.yaxis.label] +             ax.get_xticklabels() + ax.get_yticklabels()):    item.set_fontsize(20)