Subnet Calculator
Network, broadcast, usable hosts and mask from CIDR.
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About this calculator
CIDR condenses network + prefix length into one string. /24 = 256 addresses, /16 = 65,536 — each step halves or doubles the block.
Formula
Network = IP & mask; Broadcast = network | ~mask; Hosts = 2^(32−prefix) − 2 (except /31, /32).
Frequently Asked Questions
What is /32?
A single host address — no network/broadcast distinction, exactly one usable address.