Grafana Cloud Introduction Histograms and heatmaps
Grafana Cloud

# Introduction to histograms and heatmaps

A histogram is a graphical representation of the distribution of numerical data. It groups values into buckets (sometimes also called bins) and then counts how many values fall into each bucket.

Instead of graphing the actual values, histograms graph the buckets. Each bar represents a bucket, and the bar height represents the frequency (such as count) of values that fell into that bucket’s interval.

## Histogram example

This histogram shows the value distribution of a couple of time series. You can easily see that most values land between 240-300 with a peak between 260-280.

Here is an example showing height distribution of people.

Histograms only look at value distributions over a specific time range. The problem with histograms is that you cannot see any trends or changes in the distribution over time. This is where heatmaps become useful.

## Heatmaps

A heatmap is like a histogram, but over time, where each time slice represents its own histogram. Instead of using bar height as a representation of frequency, it uses cells, and colors the cell proportional to the number of values in the bucket.

In this example, you can clearly see what values are more common and how they trend over time.