library(ggplot2) a <- ggplot(mtcars, aes(x = mpg)) + geom_histogram(binwidth = 4 ) + theme(plot.margin =unit(c( 1 , 1 , 1 , 1 ) , ' cm ' )) b <- ggplot(mtcars, aes(x = mpg)) + geom_histogram(binwidth = 4 ) + theme(plot.margin =unit(c( 2 , 2 , 2 , 2 ), ' cm ' )) c <- ggplot(mtcars, aes(x = mpg)) + geom_histogram(binwidth = 4 ) + theme(plot.margin =unit(c( 3 , 3 , 3 , 3 ), ' cm ' )) d <- ggplot(mtcars, aes(x = mpg)) + geom_histogram(binwidth = 4 ) + theme(plot.margin =unit(c( 4 , 4 , 4 , 4 ) , ' cm ' )) plot_grid(a, b, c, d, nrow = 2 ,labels = c( ' aaa ' , ' bbb ' , ' ccc ' , ' ddd ' ))