In this lesson you can teach yourself how to break Y axis in chart. It is useful in case of problems with axis scale. When your data is really differential just use this trick.
1. After entering data into Excel sheet, select the data and form a desired chart through Insert > Charts.
2. Delete the grid lines through format grid lines options, select line and fill to no fill and no line through axis options. Also, delete the legends.
3. Now, right click the vertical axis and go to format axis. In format axis, enter minimum to 0 and in maximum enter the point after which you want to create the break in the graph.
4. Resize the chart by dragging down the inner handles.
5. Now make a duplicate copy of the chart. Select the chart and press ctrl +D to make a duplicate copy. Remove the borders of the chart by selecting no line under no border options. In format axis option, change the minimum to the point where you want to resume your chart after the break. Your chart will become like this:
6. Place this new chart over the old chart:
Also, insert the marker (though Insert >Shapes) as to show a break between the data.
7. In the final step, add labels, legends and axis titles.
Further reading: How to Break Chart’s column?