Statistics Tip: What's the difference between a Bar Chart and a Histogram?

Both Bar Charts and Histograms use the height of bars (rectangles of the same width) to visually depict data. So, they look similar.
 
But, they 

1. differ in whether the bars are separated or placed together (contiguous)
2. depict different types of data, and 
3. used for different purposes

 
1. Separated or contiguous

• Bar Charts: separated

• Histograms: contiguous

 
2. Types of data

• Bar Charts: Counts or Percentages of Nominal (also known as "Categorical") data. 
• Histograms: Counts or Percentages or Probabilities of the number of data points within a Range  

 
3. How Used

• Bar Charts are used to display the relative Sizes (which named item has the highest (or lowest) Count
• Histograms are used to display the Shape of the Distribution of the data. The data in the illustration above is roughly Normally Distributed.