In scenarios where you have Bar Charts with multiple series it is possible to control the width of the Bars by using the ItemWidthPercent property of the ChartArea. You can also control to what percentage the bars will overlap the preceding bar series with the ItemOverlapPercent property. Overlapping is especially useful when a long series of items needs to fit in a small-size chart. If you set negative value for ItemOverLapPercent, a gap appears between the bars of different series.