How do I ensure the map scale is accurate?

On the ‘Tools’ toolbar, select ‘Zoom to Scale’.

A small ‘Zoom to Scale’ pop-up window will appear. In order for the reference scale to display correctly, it is important to set the viewable screen width (in inches) of your display monitor. Measure the exact width of your monitor screen (in inches) and enter the appropriate screen width value. Click on the ‘Apply’ button.

If the screen width value is incorrect for your monitor, the displayed reference scale and map scale will not be the same. TIP: By default, the screen width is set to 14 inches.