The 4 main types of graphs are a bar graph or bar chart, line graph, pie chart, and diagram. Bar graphs are used to show relationships between different data series that are independent of each other. In this case, the height or length of the bar indicates the measured value or frequency. A bar graph is useful for looking at a set of data and making comparisons. For example, it’s easier to see which items are taking the largest chunk of your budget by glancing at the above chart rather than looking at a string of numbers. Bar charts can also represent more complex categories with stacked bar charts or grouped bar charts. For example, if you had two houses and needed budgets for each, you could plot them on the same x-axis with a grouped bar chart, using different colors to Describing Bar Charts and Column Charts (1) Bar charts and column charts are similar: only their orientations differ. A bar chart is orientated horizontally, whereas a column chart is arranged vertically. Sometimes "bar chart" refers to both forms. These types of charts are usually used for comparison purposes (unlike line charts, which describe change).