Hi Rich 
in the render room, go to the “Progress/Statistics” tab.
In the Rendering Progress” you’ll see the Time Left : (estimated)
It’s only available for animations, not single frame renders.
As design Acrobat mentioned, it’s tricky to give an accurate time remaining, as some frames may take more or less time to render.
It’s like getting an accurate time remaining for downloading a file, etc..
pic