Was wondering whether someone could clear something up for me. Basically I'd like to know how you calculate how many subnets you can have. I've been reading round a few places and getting a lot of conflicting information that is confusing me.

Say you wanted six subnets. Is the calculation 2^3 -2 = 6 correct? Some places I see the calculation as having to minus 2 subnets and others where you dont minus 2 so end up with eight subnets. 2^3 = 8. On a previous post here I saw it was 2^x -1.

I know you use the 2^x -2 when calculating how many hosts you can have in each subnet because take two off for the network and broadcast addresses, but if someone could tell me what calcuation is actually used for the number of subnets I'd greatly appreciate it.

**Edited by jp2007, 11 September 2007 - 12:34 AM.**