A Butterfly Chart (also called Tornado Chart) is a type of bar chart聽where two sets of data series are displayed side by side. It gives a quick glance of the difference between two groups with same parameters. It is also possible to stack/place two bars on each side (for example, ‘developed countries’ and ‘developing countries’) to give a聽further division of categories.

The main use of the butterfly chart is comparison of two data sets sharing the same parameters. It聽has a lot of similarity with the population pyramid, but where the population pyramid is only for population data, the butterfly chart has a broader use as a comparison chart.