Increase Width of Median Line in Boxplot Using ggplot2 in R

The default width of the median line is wider than the rest of the lines that represent minimum, first quartile, third quartile or maximum but we can make it a little wider to make it more appealing. This can be done with the help of fatten argument inside geom_boxplot function, the default value of fatten is 2.

Example

 Live Demo

Consider the below data frame −

x<−sample(c("A","B","C"),20,replace=TRUE)
y<−rnorm(20,5,1.24)
df<−data.frame(x,y)
df

Output

   x    y
1 A 4.740834
2 C 5.365280
3 B 5.250932
4 B 5.764159
5 B 4.053119
6 B 4.241961
7 B 6.285087
8 C 5.513231
9 B 5.888086
10 B 4.479830
11 C 4.217874
12 A 6.366376
13 C 6.278470
14 C 4.721193
15 B 5.387542
16 B 6.683681
17 B 6.153023
18 A 4.695209
19 C 5.715360
20 A 5.948239

Loading ggplot2 package and creating the boxplots −

Example

library(ggplot2)
ggplot(df,aes(x,y))+geom_boxplot()

Output

Creating the boxplots with wider median lines −

Example

ggplot(df,aes(x,y))+geom_boxplot(fatten=3)s

Output

Example

ggplot(df,aes(x,y))+geom_boxplot(fatten=6)

Output