what unit is this measurement please?

[liamguyorourke1984]

Hi, I'm new to Eagle.

I'm just trying to set the physical size of a PCB which I'd like to start layout out components onto.

When I resize the box which represents the outline of the board i see the x and y values change at the top left hand side of the main window (as shown in the attached image). However, I'm confused as to what unit of measure I am seeing in this dialogue. If I change the grid sizes the measurements stay the same. At a glance I assumed that measurements are in millimeters  but  when I set the board size to that of an average arduino shield it tells me that the length is 2120. so it's clearly not in millimeters.

Could someone please explain to me what unit these numbers represent?

Thanks

[mtl_asm]

Hi,

In your case it is "mil" which means 1 thousandth of an inch (.001 inch).  So that bit of info you are pointing to in your image means your grid spacing is 1 mil and you are at coordinate x =  0 mil and y = 2120 mil. 

To change to mm you can type grid into the command line and the you get some dialog which you can set the grid, alternate grid and units.