Web & Network
Calculate IPv4 subnet details from CIDR notation. Network address, broadcast, host range, and more.
IP Address with CIDR field — for example 192.168.1.0/24.Subnet Details for the network address, broadcast address, subnet mask, wildcard mask, usable host range, total hosts, and IP class.Usable IP Range to see the first and last 10 assignable addresses in the subnet.Binary Representations to view the address, mask, network, and broadcast as 32-bit binary.Plan subnets before allocating ranges. See exactly how many hosts a prefix supports and where each network begins and ends.
Confirm that a route, ACL, or firewall entry covers the right range by checking the network address, mask, and broadcast it actually describes.
Match a prefix to your device count. A /24 fits 254 hosts, a /28 fits 14 — avoid over- or under-sizing a subnet.
The tool reports the address class (A–E) so you can see how legacy classful ranges relate to modern CIDR.
Compare the dotted-decimal and 32-bit binary forms side by side to build an intuition for how masks separate network from host bits.
Every calculation runs in your browser. Nothing is uploaded, logged, or sent to a server — safe for internal IPs and real network data.
CIDR (Classless Inter-Domain Routing) combines an IP address with a prefix length, written as 192.168.1.0/24. The /24 means the first 24 bits are the network portion, leaving 8 bits for hosts.
It shows the network address, broadcast address, usable host range, total hosts, subnet mask, wildcard mask, CIDR prefix, and IP class — plus the first and last 10 usable IPs and the 32-bit binary form of each key value.
The network address is the first address in the subnet and identifies it. The broadcast address is the last address and reaches every host at once. The usable range is everything in between, which devices can actually be assigned.
The first address is reserved as the network address and the last as the broadcast address, so neither can be assigned to a device. A /24 has 256 addresses but only 254 usable hosts. /31 and /32 are special: this tool reports a single usable address for /32 and none for /31.
/31 and /32 prefixes used for?A /31 is used for point-to-point links (per RFC 3021), where only two devices talk to each other. A /32 identifies a single host, commonly used for a specific route or a loopback-style address.
No. This calculator is IPv4-only. IPv6 uses 128-bit addresses with a different notation and subnetting model, so it is not handled here.
Never. All calculations happen locally in JavaScript. Your input is not sent to, stored on, or logged by any server.