Go to google.com/maps
Search for 1st address in the search bar (circled)

Right click on the location and select “measure distance”

Search for 2nd address in the search bar- hit enter
Right click the marker and select “distance to here”

When you point your mouse over the search bar it will drop down and show you
the distance in a detail like this

You can use your scroll wheel on your mouse to zoom out and see the straight line
too 
I click the back button to go back to the first address (Subject)- you can right click
on the measurement line and clear that measurement. Then repeat –right click
“measure distance,” search for 2nd comp and then “distance to here”
*be sure to clear the first measurement or it will start adding them together!