How to set font size of Matplotlib axis Legend?

Question

I have a code like this:

import matplotlib.pyplot as plt
from matplotlib.pyplot import *
from matplotlib.font_manager import FontProperties

fontP = FontProperties()
fontP.set_size('xx-small')
fig=plt.figure()
ax1=fig.add_subplot(111)
plot([1,2,3], label="test1")
ax1.legend(loc=0, ncol=1, bbox_to_anchor=(0, 0, 1, 1),
           prop = fontP,fancybox=True,shadow=False,title='LEGEND')
plt.show()

legend fontsize

It can be seen in the plot that the setting in Fontsize does not affect the Legend Title font size.

How to set the font size of the legend title to a smaller size?

For an updated (2021), see stackoverflow.com/a/67879275/2612410 — Alejo Bernardin
– Alejo Bernardin, Commented Jun 7, 2021 at 22:17

Andy Jones · Accepted Answer · 2019-09-05 06:46:46Z

114

This is definitely an old question, but was frustrating me too and none of the other answers changed the legend title fontsize at all, but instead just changed the rest of the text. So after banging my head against the matplotlib documentation for awhile I came up with this.

legend = ax1.legend(loc=0, ncol=1, bbox_to_anchor=(0, 0, 1, 1),
           prop = fontP,fancybox=True,shadow=False,title='LEGEND')

plt.setp(legend.get_title(),fontsize='xx-small')

As of Matplotlib 3.0.3, you can also set it globally with

plt.rcParams['legend.title_fontsize'] = 'xx-small'

edited Sep 5, 2019 at 6:46

Andy Jones

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answered Jun 13, 2013 at 17:34

nothilaryy

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1 Comment

Davidmh Over a year ago

title_fontsize is now an argument you can pass to legend(...), but your answer made it discoverable for me, so thanks!

DougR · Accepted Answer · 2015-12-04 12:14:38Z

47

Here is how to change the fontsize of the legend list and/or legend title:

legend=plt.legend(list,loc=(1.05,0.05), title=r'$\bf{Title}$') #Legend: list, location, Title (in bold)
legend.get_title().set_fontsize('6') #legend 'Title' fontsize
plt.setp(plt.gca().get_legend().get_texts(), fontsize='12') #legend 'list' fontsize

edited Dec 4, 2015 at 12:14

answered Jan 24, 2013 at 10:45

DougR

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2 Comments

Tapajit Dey Over a year ago

Can you please help me in merging the code piece you have proposed with mine? I'm seeing some errors when I add this piece to the code I have. Specifically: Traceback (most recent call last): <file> in <module> legend=plt.legend(list,loc=(1.05,0.05), title=r'$\bf{Title}$') #Legend: list, location, Title (in bold) File "C:\Python26\Lib\site-packages\matplotlib\pyplot.py", line 2800, in legend ret = gca().legend(*args, **kwargs) File "C:\Python26\Lib\site-packages\matplotlib\axes.py", line 4494, in legend labels)] TypeError: zip argument #2 must support iteration

DougR Over a year ago

I've noticed these commands do not work in Spyder using the IPython console but work well in a standard python (v2.7) console. In IPython it gives 'NameError: name 'gca' is not defined' .

aquirdturtle · Accepted Answer · 2019-12-09 03:04:42Z

42

Inspired by the current top answer, I found a slightly more natural way to change the fontsizes in the legend. The fontsize argument sets the font size of each of the data labels, and the title_fontsize argument sets the fontsize of the title, if you give the legend a title.

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.plot([0,1,2],[2,1,2],label='test_data (fs=12)')
ax.legend(fontsize=12, title='TITLE (fs=30)',title_fontsize=30)

Gives a figure like this:

answered Dec 9, 2019 at 3:04

aquirdturtle

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2 Comments

Alexander McFarlane Over a year ago

this fails if custom lines/patches have been added

Iddo weiner Over a year ago

This should be the leading answer

Max · Accepted Answer · 2017-05-19 15:29:44Z

35

Banged my head against it too, here is another more flowing way of doing it:

leg = ax.legend()
leg.set_title('A great legend',prop={'size':14})

answered May 19, 2017 at 15:29

Max

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Comments

segasai · Accepted Answer · 2012-09-13 10:09:32Z

14

I don't know how to set it up for an individual plot, but I always do it globally:

plt.rc('legend',**{'fontsize':6})

answered Sep 13, 2012 at 10:09

segasai

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Comments

Alejo Bernardin · Accepted Answer · 2021-06-07 22:16:00Z

14

Now in 2021, with matplotlib 3.4.2 you can set your legend fonts with

plt.legend(title="My Title", fontsize=10, title_fontsize=15)

where fontsize is the font size of the items in legend and title_fontsize is the font size of the legend title. More information in matplotlib documentation

answered Jun 7, 2021 at 22:16

Alejo Bernardin

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Comments

Crococode · Accepted Answer · 2016-06-23 11:27:57Z

7

This is the fastest:

plt.legend(loc=2,prop={'size':6})

answered Jun 23, 2016 at 11:27

Crococode

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1 Comment

Ben Lindsay Over a year ago

This one doesn't change the title size unfortunately.

Nicola Vianello · Accepted Answer · 2012-09-13 10:18:29Z

4

I generally do in this way. Once the plot has been done i do the following

plt.legend(loc=0, numpoints=1)
leg = plt.gca().get_legend()
ltext  = leg.get_texts()
plt.setp(ltext, fontsize='small')

I don't know if this works for you

answered Sep 13, 2012 at 10:18

Nicola Vianello

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1 Comment

Ondřej Čertík Over a year ago

In ipython notebook, I just do setp(gca().get_legend().get_texts(), fontsize='small').

Bryan Ortiz · Accepted Answer · 2022-07-29 22:19:02Z

2

The most easy method is using (it served me)

ax.legend(title = "anything", title_fontsize = 8, fontsize = 6)

title_fontsize is useful for changing the fontsize of the title

edited Jul 29, 2022 at 22:19

answered Jul 27, 2022 at 17:17

Bryan Ortiz

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1 Comment

Community Over a year ago

As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center.

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