how to calculate number of nodes?

I'm wondering how to calculate number of nodes in CIDR network? for example if the CIDR network is 11.13.0.0/16 How many nodes can be accommodated in this CID开发者_如何转开发R network? Any help would be appreciatet

Typically you'll have a broadcast address, so that's one address removed. You'll also typically have a router/default gateway, so that's often one more address removed. So that leaves 2^(32-16)-2==65534 IP addresses free for other use. If you want to subnet that further, you'll lose one more IP per subnet, since each subnet will have its own broadcast range.

In general terms thats 2^(32-bits_set_in_mask) addresses. As sarnold pointed out some of those can't be used for nodes.