A bar chart (also called a bar graph) is a way to graphically display data using bars of different heights or widths. Bar charts are useful for showing comparisons between sets of data, especially when you want to show the relative size of things, such as differences in height, length or weight. Microsoft Excel can create colorful and professional looking bar charts in a few clicks — just enter the data into the worksheet and let Microsoft Excel do the rest. While bar charts can be vertical or horizontal, the most common format is a horizontal format. Microsoft Excel calls vertical graphs column charts and horizontal graphs bar charts.