Changing displayed size I have extruded a floorplan. To stay relatively close to the elements that I need to extrude, I have chosen a certain grid scale. 

However, the model size is not what I intended.

I wanted to make the front wall like 6 metres.

Is there a relatively easy way to change the mesh size so that the front wall becomes like 6 metres while keeping the grid element size?

Thank you.
After setting the scene scale in the Blender Properties panel so that the units report 6m, you can adjust the grid scale under the display properties, in the 3D view Panel (press N hovering over the 3D view), until you get the result you want.