Web & Network
Subnet Calculator
IPv4 and IPv6 CIDR ranges, masks, usable hosts and subnet splitting.
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About the Subnet Calculator
Enter an IP address with a prefix (10.0.0.0/16) or a netmask to get the network and broadcast addresses, the first and last usable hosts, the number of hosts, the wildcard mask for ACLs and the address type, such as private or carrier-grade NAT. Split a network into equal subnets, or work out IPv6 prefixes.
How to use it
- Enter an address with /prefix or a netmask.
- Read the calculated range.
- Optionally split the network into smaller subnets.
Frequently asked questions
- How many hosts are in a /24?
- 256 addresses, 254 usable. /31 networks have 2 usable addresses (RFC 3021) and /32 is a single host.
- What is a wildcard mask?
- The inverse of the netmask (0.0.0.255 for /24), used in Cisco ACLs and OSPF.
- Does it support IPv6?
- Yes: network, first and last address and address count for any IPv6 prefix, with RFC 5952 compression.