IPv4 & IPv6 · runs in your browser
Subnet Calculator
Calculate IPv4 and IPv6 subnets: network and broadcast address, usable host range, mask, wildcard and CIDR, and split a block into subnets.
Subnet divider
Split 192.168.1.0/24 into smaller subnets
| Network | Broadcast | First host | Last host | Usable |
|---|---|---|---|---|
| 192.168.1.0 | 192.168.1.63 | 192.168.1.1 | 192.168.1.62 | 62 |
| 192.168.1.64 | 192.168.1.127 | 192.168.1.65 | 192.168.1.126 | 62 |
| 192.168.1.128 | 192.168.1.191 | 192.168.1.129 | 192.168.1.190 | 62 |
| 192.168.1.192 | 192.168.1.255 | 192.168.1.193 | 192.168.1.254 | 62 |
| Prefix | Subnet mask | Wildcard | Usable hosts | Common use |
|---|---|---|---|---|
| /8 | 255.0.0.0 | 0.255.255.255 | 16,777,214 | Very large network (Class A) |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,534 | Large network (Class B) |
| /24 | 255.255.255.0 | 0.0.0.255 | 254 | Typical LAN (Class C, 254 hosts) |
| /25 | 255.255.255.128 | 0.0.0.127 | 126 | Half C — 126 hosts |
| /26 | 255.255.255.192 | 0.0.0.63 | 62 | 62 hosts |
| /27 | 255.255.255.224 | 0.0.0.31 | 30 | 30 hosts |
| /28 | 255.255.255.240 | 0.0.0.15 | 14 | 14 hosts |
| /29 | 255.255.255.248 | 0.0.0.7 | 6 | 6 hosts |
| /30 | 255.255.255.252 | 0.0.0.3 | 2 | Point-to-point (2 hosts) |
| /31 | 255.255.255.254 | 0.0.0.1 | 2 | P2P link (RFC 3021) |
| /32 | 255.255.255.255 | 0.0.0.0 | 1 | Single host / loopback |
About this tool
This subnet calculator turns any IPv4 or IPv6 CIDR block into the numbers you actually need: network and broadcast addresses, the usable host range, total and usable host counts, the subnet mask and its wildcard mask. Enter an address with a prefix (for example 10.0.0.0/24) and everything updates instantly.
It also splits a parent network into equal subnets, so you can plan VLSM addressing for a new site or validate an existing scheme before you push it to a router. Every calculation runs locally in your browser — no address plan is ever sent to a server.
Frequently asked questions
How many usable hosts are in a /24?+
A /24 has 256 addresses, 254 of them usable for hosts. The first is the network address and the last is the broadcast address, which is why you subtract two.
Does it support IPv6?+
Yes. Enter an IPv6 address with a prefix length (for example 2001:db8::/48) and the tool returns the network range and address counts using IPv6 rules, where there is no broadcast address.
What is a wildcard mask used for?+
Wildcard masks are the inverse of a subnet mask and are used in ACLs and OSPF on Cisco-style devices. The calculator shows both so you can copy whichever your config needs.