What Is a Histogram?

What a histogram is

A histogram is a chart that shows how a set of numbers is distributed. It splits the range of your data into equal intervals called bins, then draws a bar over each bin whose height is the count of values that fall inside it. Put simply, it shows you where your numbers pile up and where they thin out.

Bins are the whole idea

Every histogram is built on bins. A bin is one slice of the number line, like 10 to 20, and the bar above it counts how many data points land in that slice. Because bins are ranges that touch end to end, the bars sit flush against each other with no gaps. Change the bin width and you change the picture, which is why choosing bins well matters so much.

What you learn from it

• Center: where the tall bars are, roughly the typical value.
• Spread: how wide the bars stretch, from tight to very spread out.
• Shape: symmetric, skewed left or right, one peak or two.
• Outliers: lonely bars far from the rest.

A quick example

Imagine test scores from a class. A histogram groups them into ranges like 60 to 70, 70 to 80, and so on, then shows how many students landed in each range. One glance tells you whether the class clustered high, spread out evenly, or split into two groups. Try it on your own data with the histogram maker, and see the difference from a bar chart on the histogram vs bar chart page.