About the Subnet Calculator
Plan and troubleshoot IPv4 networks. Enter an IP address with a CIDR prefix or subnet mask to get the network and broadcast addresses, usable host range, number of hosts, wildcard mask, address class and a binary breakdown.
How to use it
- Enter an IPv4 address.
- Pick the prefix (/0 – /32) or subnet mask.
- Review the subnet details and binary view.
Formula & method
Network = IP AND mask
Broadcast = Network OR NOT mask
Usable hosts = 2^(32 − prefix) − 2Frequently asked questions
Why are two addresses not usable?
In a normal subnet the first address identifies the network and the last is the broadcast address. /31 point-to-point links and /32 single hosts are exceptions.
Results are estimates for general information only and are not financial, tax, legal or medical advice. Please confirm important decisions with a qualified professional.