Navigate
Home Compendium
Exercises
Tidyverse packages
dplyr ggplot2 tidyr stringr lubridate purrr forcats readr broom Tidyverse R for Data Science
Deep dives
dplyr Joins dplyr Window Functions dplyr group_by ggplot2 Themes ggplot2 Facets ggplot2 Color Scales ggplot2 Bar Charts ggplot2 Heatmaps tidyr Pivot tidyr Nest/Unnest Regex
Wrangling & EDA
Data Wrangling Data Cleaning EDA Data Visualization data.table dbplyr / SQL Web Scraping API Calls
Statistics
Hypothesis Testing Linear Regression Logistic Regression Correlation Probability Distributions
Machine Learning
Machine Learning tidymodels Random Forest XGBoost Clustering PCA Cross-Validation
Time Series
Time Series ARIMA
By Industry
Finance Marketing Analytics Healthcare Biostatistics Genomics Sports Analytics A/B Testing
Reporting & Apps
Shiny R Markdown
Levels
R for Beginners R Interview Questions
R r‑statistics.co

ggplot2 geom_ribbon() in R: Filled Area Between Two Lines

The geom_ribbon() function in ggplot2 fills the AREA between two y values (ymin and ymax) at each x. It is the standard tool for confidence bands, prediction intervals, and any "range over time" plot.

By Selva Prabhakaran  ·  Published May 12, 2026  ·  Last updated May 12, 2026
⚡ Quick Answer
ggplot(df, aes(x, ymin = lo, ymax = hi)) + geom_ribbon()
ggplot(df, aes(x, y, ymin = lo, ymax = hi)) + geom_ribbon(alpha = 0.3) + geom_line()
geom_ribbon(fill = "steelblue", alpha = 0.4)
geom_area(...)                        # different: from 0 baseline

Need explanation? Read on for examples and pitfalls.

📊 Is geom_ribbon() the right tool?
STARTarea between two y curvesgeom_ribbon()area from 0 to ygeom_area()prediction interval bandgeom_ribbonerror bars per pointgeom_errorbar()shaded confidence band on a line plotgeom_ribbon + geom_line

What geom_ribbon() does in one sentence

geom_ribbon() draws a filled area at each x bounded by ymin (bottom) and ymax (top). The most common use: confidence bands around a fit line.

Syntax

geom_ribbon(mapping = NULL, data = NULL, alpha = 0.3, ...). Requires aes(ymin, ymax).

Run live
Run live, no install needed. Every R block on this page runs in your browser. Click Run, edit the code, re-run instantly. No setup.
RConfidence band around mean
library(ggplot2) library(dplyr) mtcars |> group_by(cyl) |> summarise(mean_mpg = mean(mpg), sd_mpg = sd(mpg)) |> ggplot(aes(cyl, mean_mpg)) + geom_ribbon(aes(ymin = mean_mpg - sd_mpg, ymax = mean_mpg + sd_mpg), alpha = 0.3) + geom_line()

  

  





Tip
Always pair geom_ribbon with geom_line for the central trend. The ribbon shows uncertainty; the line shows the estimate.



Five common patterns



1. Confidence band




  

    
RMean ± SD ribbon

    
df |>
  ggplot(aes(x, mean)) +
  geom_ribbon(aes(ymin = mean - sd, ymax = mean + sd), alpha = 0.3) +
  geom_line()

    

      
      
    

    

  

  





2. Prediction interval




  

    
RFrom a model

    
predictions |>
  ggplot(aes(x, fit)) +
  geom_ribbon(aes(ymin = lwr, ymax = upr), fill = "steelblue", alpha = 0.3) +
  geom_line(color = "steelblue")

    

      
      
    

    

  

  





3. Min-max range




  

    
RRange over time

    
df |>
  ggplot(aes(date, ymin = min_temp, ymax = max_temp)) +
  geom_ribbon(fill = "tomato", alpha = 0.4)

    

      
      
    

    

  

  





4. Multiple ribbons (groups)




  

    
RPer-group bands

    
df |>
  ggplot(aes(x, fit, ymin = lo, ymax = hi, fill = group)) +
  geom_ribbon(alpha = 0.3) +
  geom_line(aes(color = group))

    

      
      
    

    

  

  





5. Combine with stat_smooth




  

    
RAuto-computed band

    
ggplot(mtcars, aes(wt, mpg)) +
  geom_smooth(method = "lm")  # fills band automatically
#> Equivalent to ribbon + line of model fit

    

      
      
    

    

  

  





Key Insight
geom_smooth() internally uses geom_ribbon + geom_line to draw the fit line and confidence band. When you need MORE control (custom intervals, prediction bands), build with geom_ribbon + geom_line directly.



geom_ribbon() vs geom_area() vs geom_errorbar()







Function
Bounds
Best for






geom_ribbon()
ymin to ymax
Confidence bands, ranges




geom_area()
0 to y
Filled areas from baseline




geom_errorbar()
ymin to ymax (vertical bars)
Per-point uncertainty







A practical workflow



The "fit + band" pattern is geom_ribbon's signature use.




  

    
RInteractive R

    
fit <- lm(mpg ~ wt, data = mtcars)
preds <- predict(fit, interval = "confidence") |>
  as_tibble() |>
  bind_cols(mtcars)

ggplot(preds, aes(wt, mpg)) +
  geom_ribbon(aes(ymin = lwr, ymax = upr), alpha = 0.3) +
  geom_line(aes(y = fit), color = "steelblue") +
  geom_point()

    

      
      
    

    

  

  





Manual confidence band from a linear model.



Common pitfalls



Pitfall 1: forgetting alpha. Default fill is solid. Set alpha = 0.3 for translucency so the line and points underneath remain visible.



Pitfall 2: forgetting the line. A ribbon alone is just a shaded area. Add geom_line for the central trend.



Warning
geom_ribbon fills BETWEEN ymin and ymax, the line itself is NOT drawn. Always pair with geom_line for the visible trend.



Try it yourself





Try it: Plot mtcars wt vs mpg with a fit line and 95% confidence band using lm. Save to ex_plot.



  

    
RYour turn: fit + band

    
fit <- lm(mpg ~ wt, data = mtcars)
preds <- predict(fit, interval = "confidence") |> as.data.frame() |> bind_cols(mtcars)

ex_plot <- # your code here

    

      
      
    

    

  

  





Click to reveal solution



  

    
RSolution

    
ex_plot <- ggplot(preds, aes(wt, mpg)) +
  geom_ribbon(aes(ymin = lwr, ymax = upr), alpha = 0.3, fill = "steelblue") +
  geom_line(aes(y = fit), color = "steelblue") +
  geom_point()

    

      
      
    

    

  

  





Explanation: ribbon for the band; line for the fit; points for raw data.










After mastering geom_ribbon, look at:



    


  • geom_area(): from baseline 0
    • 


  • geom_smooth(): auto fit + band
    • 


  • geom_errorbar() / geom_errorbarh(): per-point bars
    • 


  • geom_pointrange(): point with range
    • 


  • stat_summary(): compute summaries on the fly
    • 





FAQ



What does geom_ribbon do in ggplot2?



geom_ribbon() fills the area between ymin and ymax at each x. Used for confidence bands, prediction intervals, and ranges over time.



What is the difference between geom_ribbon and geom_area?



geom_ribbon fills between ymin and ymax (two curves). geom_area fills from baseline 0 to y (one curve).



How do I make geom_ribbon translucent?



Set alpha = 0.3 (or smaller). Default is opaque, which obscures lines underneath.



Should I use geom_smooth or geom_ribbon for confidence bands?



geom_smooth for automatic fit + band. geom_ribbon for manual control over the band's data.



Can I use geom_ribbon with multiple groups?



Yes. Pass fill = group in aes; each group gets its own ribbon. Pair with geom_line(color = group) for trends.



          

        


        
      


      

        

        
© 2016-2026 Selva Prabhakaran.
          This work is licensed under the Creative Commons License.
        

        

          About ·
          RSS