When your calendars are in Side-by-Side view all of the calendar columns will be the same width:

Some of your calendars in Side-by-Side view may have more data than others. This can push a lot of your calendar data further down on the screen since it's limited to a smaller column. In this case, you can change the width of the last calendar in Side-by-Side view. 

If you put your calendar with the most calendar data in the last column, then you can see more of the calendar data at once with a wider column. See the image below:

To change the width of your Side-by-Side calendar columns follow the steps in the image below: