Refer to the style tab on the Data Vis overview page for base graph style specifications.
The height of a bar varies based on the value for that data increment. The width of a bar is calculated based on the width of the graph and the number of bars. In other words, the more bars there are in a graph the thinner the bars will be and vice versa.
A grouped bar graph follows the same width and height rules for a single bar graph data set. Spacing between groups of bar graphs is larger than bars within a group. Maintain a minimum of 2px between bars within a group to meet color contrast standards.