Change Major and Minor Units of Value Axis in PowerPoint 2010 for Windows

While learning about chart axes, you will come across two terms, major and minor units. These are the intervals at which the axis spaces itself. As the name suggest, you can choose to space the axis at two levels: major and minor. Look at Figure 1, below and you'll see a chart that has both major and minor units displayed on the value axis. All units pointed with blue arrows are major, and green arrows point to minor units.

Figure 1: Major and minor units displayed on the value axis

By default, PowerPoint sets the major and minor units on its own. Many times, this may be exactly what you need. At other times, you may want to set your own intervals for the major and minor units for several reasons. Before you do so, a word of caution: do remember that any of these changes can have three implications:

1. Values

Values that you see placed on the value axis reflect the major units you choose. However, any changes you make to minor units do not influence the displayed values, since values of minor units are not typically displayed on the axis.

2. Tick Marks

Tick marks you see change depending upon intervals you choose for both major and minor units. Of course, it all depends upon whether you have opted to display tick marks or not. Refer to our Tick Marks on Chart Axes in PowerPoint 2010 tutorial to learn more.

3. Gridlines

Gridlines shown change as well. Again, the appearance of these gridlines will be influenced by whether you have made them visible or not.

The major unit influences spacing between major tick marks on the value axis. Similarly, the minor unit influences spacing between minor tick marks on the value axis. By default these values are automatically decided by the Minimum and Maximum scale values on the value axis. Still, you can change them to suit your needs, as explained in this tutorial.

Follow these steps to learn about changing major and minor units within chart axes in PowerPoint 2010 for Windows:

1. To start with, you need a chart inserted on your slide. For this tutorial we have selected a column chart, as shown in Figure 2, below. As you can see, the default chart shows only major units for both tick marks and gridlines. No minor units are represented here.
2. 
   Figure 2: Chart inserted
2. To see the effect of the minor units on your chart, enable minor tick marks on the vertical (value) axis, as shown in Figure 3, below.
3. 
   Figure 3: Minor tick marks visible on the vertical (value) axis
3. Now, carefully right-click on the vertical (value) axis (the axis towards the left of the plot area) to select it. Then, right-click to bring up a contextual menu that you see in Figure 4, below. Select the Format Axis option, as shown in Figure 4. If you do not see the Format Axis option in the contextual menu, you may have right-clicked on another chart element. Make sure you then deselect everything in the chart, and then right-click on the value axis again.
4. 
   Figure 4: Format Axis option for the vertical (value) axis
4. Doing so summons the Format Axis dialog box. Make sure that the Axis Options is selected in the sidebar, as shown in Figure 5, below. Note that Major unit option is set to Auto by default which is indicated by the selected status of the Auto radio button associated with it. Also note that it is set to 1.0, as shown highlighted in red within Figure 5.
5. 
   Figure 5: Format Axis dialog box
5. Now, let us change the Major unit value. Select the Fixed radio button associated with the major unit value to remove it from Auto mode, and enter the new value in the box, as shown highlighted in red within Figure 6, below. We changed the value to 2.
6. 
   Figure 6: Major unit value changed
6. When done, click the Close button to apply the change made, and get back to the chart. In Figure 7, you can see that the value axis' major unit values now show an interval of 2 points. Doing so makes the chart look cleaner and gives it more visual breathing space. Compare Figures 3 and 7.
7. 
   Figure 7: Major unit value change reflecting on the chart
7. To change the minor unit, access the Format Axis dialog box again (see Steps 3 and 4). Make sure that Axis Options is active in the sidebar as shown in Figure 8. As you can see in Figure 8, the default Minor unit value is set to 0.2 (highlighted in red within Figure 8).
8. 
   Figure 8: Default Minor unit value within Format Axis dialog box
8. Now, select the Fixed radio button associated with the Minor unit to remove it from Auto mode, and add the new required value in the box. We changed the value to 0.1, as shown highlighted in red within Figure 9, below.
9. 
   Figure 9: Minor unit value changed within Format Axis dialog box
9. When done, click the Close button to apply the change and get back to the chart. In Figure 10, you can see that the value axis' Minor unit values now show a difference of 0.1 points. Compare Figures 3 and 10.
10. 
    Figure 10: Minor unit value change reflecting on the chart
10. Save your presentation.