160

How can we change y axis to percent like the figure? I can change y axis range but I can't make it to percent. enter image description here

Mus
  • 7,290
  • 24
  • 86
  • 130

4 Answers4

341

Use:

+ scale_y_continuous(labels = scales::percent)

Or, to specify formatting parameters for the percent:

+ scale_y_continuous(labels = scales::percent_format(accuracy = 1))

(the command labels = percent is obsolete since version 2.2.1 of ggplot2)

mkirzon
  • 413
  • 5
  • 9
luchonacho
  • 6,759
  • 4
  • 35
  • 52
  • 6
    I liked that you don't have to type `library(scales)` for this. – Akshay Gaur Sep 14 '18 at 02:50
  • And the reason `scales::percent(accuracy = 1)` does not work is because the `*_format()` versions create a function instead of...whatever `percent()` alone creates, is that correct? – MokeEire Apr 19 '19 at 01:24
101

In principle, you can pass any reformatting function to the labels parameter:

+ scale_y_continuous(labels = function(x) paste0(x*100, "%")) # Multiply by 100 & add %

Or 

+ scale_y_continuous(labels = function(x) paste0(x, "%")) # Add percent sign

Reproducible example: 

library(ggplot2)
df = data.frame(x=seq(0,1,0.1), y=seq(0,1,0.1))

ggplot(df, aes(x,y)) + 
  geom_point() +
  scale_y_continuous(labels = function(x) paste0(x*100, "%"))
Deena
  • 5,925
  • 6
  • 34
  • 40
  • 13
    +1 for no external dependency. I know that since Hadley is the author of both ggplot2 and scales, it shouldn't really matter—but this solution is still appreciated. – Mark White Mar 08 '18 at 21:03
52

ggplot2 and scales packages can do that:

y <- c(12, 20)/100
x <- c(1, 2)

library(ggplot2)
library(scales)
myplot <- qplot(as.factor(x), y, geom="bar")
myplot + scale_y_continuous(labels=percent)

It seems like the stat() option has been taken off, causing the error message. Try this:

library(scales)

myplot <- ggplot(mtcars, aes(factor(cyl))) + 
          geom_bar(aes(y = (..count..)/sum(..count..))) + 
          scale_y_continuous(labels=percent)

myplot
Michael Ohlrogge
  • 10,559
  • 5
  • 48
  • 76
Penguin_Knight
  • 1,289
  • 8
  • 13
6

Borrowed from @Deena above, that function modification for labels is more versatile than you might have thought. For example, I had a ggplot where the denominator of counted variables was 140. I used her example thus:

scale_y_continuous(labels = function(x) paste0(round(x/140*100,1), "%"), breaks = seq(0, 140, 35))

This allowed me to get my percentages on the 140 denominator, and then break the scale at 25% increments rather than the weird numbers it defaulted to. The key here is that the scale breaks are still set by the original count, not by your percentages. Therefore the breaks must be from zero to the denominator value, with the third argument in "breaks" being the denominator divided by however many label breaks you want (e.g. 140 * 0.25 = 35).

DanM
  • 337
  • 3
  • 9
  • If I was repeating this chart several times but the denominator changes each time, how could I change the above coding so that I wouldn't have to manually look up the denominator for each chart? – missanita Aug 22 '23 at 02:09