Calculate network, broadcast, usable hosts, and IPv6 prefixes in your browser. Nothing is uploaded or stored.
A subnet calculator works out the boundaries of an IP network from an address and a prefix length or netmask. For IPv4 it gives the network and broadcast addresses, the usable host range, the wildcard mask and the number of hosts; for IPv6 it gives the prefix, the first and last address and the address count. Everything is calculated in your browser.
192.168.1.130.26 or /26) or, for IPv4, as a dotted netmask (255.255.255.192). IPv6 takes a prefix length only.For 192.168.1.130/26:
| Field | Result | Meaning |
|---|---|---|
| Network | 192.168.1.128 | The first address, identifying the subnet itself |
| Broadcast | 192.168.1.191 | The last address, used to reach every host on the subnet |
| First / last usable | .129 – .190 | The addresses you can assign to devices |
| Wildcard | 0.0.0.63 | The inverted netmask, used in Cisco ACLs and OSPF |
| Host count | 62 | Usable addresses: 2(32 − prefix) minus the network and broadcast addresses |
| Scope | private | "private" for private, loopback, link-local and carrier-grade NAT ranges; otherwise "public" |
Two prefixes are special: a /31 has two usable addresses and no network or broadcast address (used for point-to-point links, RFC 3021), and a /32 is a single host.
IPv6 has no broadcast address, so the results show the prefix, first and last address, and the number of addresses as a power of two. A /64 is the standard size for a single LAN segment (address autoconfiguration needs it), and sites are commonly given a /48 or /56 to divide into /64s.
| Prefix | Netmask | Usable hosts |
|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 |
| /16 | 255.255.0.0 | 65,534 |
| /20 | 255.255.240.0 | 4,094 |
| /22 | 255.255.252.0 | 1,022 |
| /23 | 255.255.254.0 | 510 |
| /24 | 255.255.255.0 | 254 |
| /25 | 255.255.255.128 | 126 |
| /26 | 255.255.255.192 | 62 |
| /27 | 255.255.255.224 | 30 |
| /28 | 255.255.255.240 | 14 |
| /29 | 255.255.255.248 | 6 |
| /30 | 255.255.255.252 | 2 |
| /31 | 255.255.255.254 | 2 (point-to-point) |
| /32 | 255.255.255.255 | 1 (single host) |
254. A /24 has 256 addresses; the first is the network address and the last is the broadcast address, leaving 254 for devices.
CIDR (Classless Inter-Domain Routing) writes a network as an address plus the number of leading bits that identify the network, such as 10.0.0.0/8. The remaining bits identify hosts within it.
The netmask with every bit inverted: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it, where a 0 bit means "must match" and a 1 bit means "any value".
Cloud networks reserve extra addresses in each subnet. AWS VPCs and Azure virtual networks, for example, reserve five per subnet (the first four and the last), so a /24 there has 251 usable addresses instead of 254.