Stacked bar graph in R

Data

Consider the data of the following table, which shows the count of the values of the variable x within three different groups.

# Data 
set.seed(1)
x <- sample(1:4, size = 50, replace = TRUE)
g <- sample(c("Group 1", "Group 2", "Group 3"),
            size = 50, replace = TRUE)

# Create a table from your data
tabl <- table(x, g)
tabl

x	Group 1	Group 2	Group 3
1	3	8	5
2	5	7	4
3	4	3	4
4	4	1	2

Stacked bar chart

In order to create a stacked bar chart, also known as stacked bar graph or stacked bar plot, you can use barplot from base R graphics. Note that you can add a title, a subtitle, the axes labels with the corresponding arguments or remove the axes setting axes = FALSE, among other customization arguments.

barplot(tabl,
        main = "Stacked bar chart",
        sub = "Subtitle",
        xlab = "X-lab",
        ylab = "Y-lab",
        axes = TRUE)

Basic stacked bar chart in R

Horizontal bar chart

If you prefer a horizontal stacked bar chart rather than vertical set horiz = TRUE.

barplot(tabl,
        horiz = TRUE)

Horizontal bar chart in R

Custom group names

The function also allows modifying the names of the groups displayed along the X-axis (Y-axis for horizontal bar plots) with names.arg argument.

barplot(tabl,
        names.arg = c("G1", "G2", "G3"))

Stacked bar graph with custom names

Fill color and borders

Stacked bar graph colors with barplot function

Color palette

If you want to customize the color palette use col argument. You will need to specify as many colors as rows your table has. Check the color palette section to choose your palette.

barplot(tabl, col = c("#993404", "#FB6A4A",
                      "#FED976", "#FFFFCC"))

Border color of the stacked bar chart in R

Border color

The border color, which defaults to black, can be customized with border argument.

# Stacked bar plot with brown border
barplot(tabl, col = c("#993404", "#FB6A4A",
                      "#FED976", "#FFFFCC"),
        border = "brown")

Stacked bar plot without borders in R

Remove the borders

If you prefer to remove all the borders set border = NA.

# Stacked bar plot without border
barplot(tabl, col = c("#993404", "#FB6A4A",
                      "#FED976", "#FFFFCC"),
        border = NA)

Adding a legend to the stacked plot

Adding a legend

The barplot function comes with an argument named legend.text, which allows adding a legend to the bar graph without using the legend function.

# Stacked bar plot with legend
barplot(tabl, col = c("#993404", "#FB6A4A",
                      "#FED976", "#FFFFCC"),
        legend.text = rownames(tabl))

Adding a legend to a stacked bar chart

Legend customization

If you want to customize the legend you can pass the arguments of the legend function to args.legend argument as a list.

# Stacked bar plot with legend
barplot(tabl, col = c("#993404", "#FB6A4A",
                      "#FED976", "#FFFFCC"),
        legend.text = rownames(tabl),
        args.legend = list(x = "topleft"))

Stacked bar plot legend customization

Legend outside the bar chart

You may have noticed that the legend is over the bar chart in our example. If you want to place the legend outside the chart increase the corresponding margin and fine tune the position of the legend with inset as in the following example.

# Increase the right margin
par(mar = c(5.1, 4.1, 4.1, 4))

# Stacked bar chart with legend
barplot(tabl,
        col = c("#993404", "#FB6A4A",
                "#FED976", "#FFFFCC"),
        legend.text = rownames(tabl), 
        args.legend = list(x = "topright",
                           inset = c(-0.2, 0)))

R Stacked bar plot with legend outside the plot