Subnet Calculator
Enter an IPv4 address with a CIDR prefix or subnet mask. Get network address, broadcast, host range, wildcard mask, and binary breakdown — instantly, in your browser.
| Field | Octet 1 | Octet 2 | Octet 3 | Octet 4 |
|---|
| CIDR | Subnet mask | Wildcard | Hosts | Typical use |
|---|---|---|---|---|
| /8 | 255.0.0.0 | 0.255.255.255 | 16,777,214 | Class A (10.x.x.x) |
| /12 | 255.240.0.0 | 0.15.255.255 | 1,048,574 | 172.16.0.0 private block |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,534 | Class B / large campus |
| /20 | 255.255.240.0 | 0.0.15.255 | 4,094 | Medium campus VLAN |
| /22 | 255.255.252.0 | 0.0.3.255 | 1,022 | Large office floor |
| /23 | 255.255.254.0 | 0.0.1.255 | 510 | Office floor |
| /24 | 255.255.255.0 | 0.0.0.255 | 254 | Standard LAN / VLAN |
| /25 | 255.255.255.128 | 0.0.0.127 | 126 | Split LAN |
| /26 | 255.255.255.192 | 0.0.0.63 | 62 | Small VLAN |
| /27 | 255.255.255.224 | 0.0.0.31 | 30 | Small segment |
| /28 | 255.255.255.240 | 0.0.0.15 | 14 | Server cluster |
| /29 | 255.255.255.248 | 0.0.0.7 | 6 | Small cluster |
| /30 | 255.255.255.252 | 0.0.0.3 | 2 | Point-to-point link |
| /31 | 255.255.255.254 | 0.0.0.1 | 2* | P2P (RFC 3021) |
| /32 | 255.255.255.255 | 0.0.0.0 | 1 | Host route |
Frequently asked questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation appends a slash and a number to an IP address — like 192.168.1.0/24 — to indicate how many bits of the address are the network portion versus the host portion.
How do I calculate usable hosts in a subnet?
Enter your IPv4 address with its CIDR prefix or subnet mask and the tool instantly shows the network address, broadcast address, host range, wildcard mask, and total usable hosts.
Does this tool support IPv6?
Not currently — this calculator is built for IPv4 subnetting (CIDR prefixes and subnet masks).
What's the difference between the network address and broadcast address?
The network address is the first address in a subnet and identifies the subnet itself; it can't be assigned to a host. The broadcast address is the last address in the subnet and is reserved for sending to every host on that subnet.
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