I'm going to be finishing my basement and needing to look at my current full 100A panel and expanding it. Currently has the following circuits:
20A kitchen
20A kitchen
40A range
20A water heater
15A basement lights
30A air cond
15A lights
15/15A furnace
15A lights
20A washing machine
30A dryer
60A garage
Isn't the garage breaker fairly large? There is a welder outlet on 30A breaker however it's currently not used. Just a gas furnace, door opener and outlets)

So with these 12 my panel is full and I'm considering adding a subpanel. I figure the basement lights cct I could put in the breaker to feed the subpanel so I could move all the basement lines to the subpanel.
However, I'm not familiar enough with what size of breaker I would need to run to the subpanel. The basement finish is going to have 2 BRs (1 legal/other using for storage/closet) a bath and a family/computer room.
For circuits I figured:
1 15A for BR1 outlets
1 15A for BR2 outlets
1 15A for BR1/BR2 lights
1 for bath (GFI... size? 20A?)
1 15A for FR lights
1 15A for FR outlets
1 15A dedicated for computer/theater equip

What size panel would I use for the sub and the breaker to feed it?

Thank you.
Jason

Jason,

You are going at sizing you calculated load backwards.

You start by getting the outside dimensions of the home and then figuring out the sq. footage and then subtracting out any unusable space. Then the complicated calculations start.

I suggest that you contact a licensed electrician and have the calculated load study completed. That way you will know whether you have to increase you service to do the additional basement work.

Also, you would then know the cable size you need to the sub panel in the basement and the correct panel size.

If the existing service is to small, you will cause more problems than you can imagine.

Also, as required in the NEC 2008, you are going to have to place the circuits in the basement on Arc Fault Circuit Breakers.

Consider an upgrade to a 200 amp service... expensive, but needed.