CIDR Calculator
Calculate detailed network information from CIDR notation. Get the network address, broadcast address, first and last usable IPs, total hosts, and subnet mask from any CIDR block.
Enter a CIDR notation (e.g., 192.168.1.0/24) to calculate subnet information
FAQ
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation represents an IP address and its network prefix. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for hosts.
How do I calculate usable hosts from CIDR?
For IPv4, usable hosts = 2^(32-prefix) - 2. We subtract 2 for the network address and broadcast address. A /24 network has 2^8 - 2 = 254 usable hosts.
What is the difference between /24 and /16?
A /24 network has 256 total addresses (254 usable), while a /16 network has 65,536 total addresses (65,534 usable). The smaller the prefix number, the larger the network.