All Bad_Daddy said is true however.....................

Go to geistware.com with your measurements and type them in. Hit the "DO ALL THE FIGURING FOR ME" button and Taa Daa!!!!!!!!

You need a couple of very easy to measure measurements. Look in the light purple box on geistware's page for what they are.
And it's blinding fast to plug in a couple more stability margin values and almost instantly have everything refigured for you. You plug in 20% SM to see where the forward CG would be, then a 10% to see where the rear would be, and you got the CG range for your airplane. In a heartbeat.

http://www.geistware.com/rcmodeling/cg_super_calc.htm