To make the data in a chart easier to read, you can add major and minor chart gridlines that extend from the tick marks on a category (x) axis (axis: A line bordering the chart plot area used as a frame of reference for measurement. The y axis is usually the vertical axis and contains data. The x-axis is usually the horizontal axis and contains categories.) or value (y) axis across the plot area (plot area: In a 2-D chart, the area bounded by the axes, including all data series. In a 3-D chart, the area bounded by the axes, including the data series, category names, tick-mark labels, and axis titles.) of the chart.
Note If you don't see the Chart menu, make sure that a chart is selected.
Note Chart gridlines are different from cell gridlines on a worksheet (worksheet: The primary document that you use in Excel to store and work with data. Also called a spreadsheet. A worksheet consists of cells that are organized into columns and rows; a worksheet is always stored in a workbook.). For more information, see Show or hide gridlines on a worksheet.