Right-click the axis and choose Format Axis. On the Scale tab, enter a new figure in the Major Unit box. The Scale tab also lets you make a point with your chart. For example, Excel probably topped the chart out at 500 if the highest charted value is 482. If you want to drive home how far this was from the goal of 1,000, change the scale’s maximum value to 1,000. You also may want to change the minimum value. If you’re charting something like Death Valley’s high temperatures on a line chart, you’re wasting space by starting the scale at zero.