Excel automatically distributes these points along a uniform X axis. To add more data to the Y axis in a line chart, add additional numbers in cells below your existing data.

How Excel Charts Work A chart has an x-axis range and a y-axis range to show the correlation between two different data sets. The x-axis is the horizontal category line.

How to create a Line Chart in Excel To create a line chart in Excel, the procedure is as follows: Select the data across both the columns (from A3 to B12). Go to Insert > Line Chart.