How are /31 and /32 handled?

/32 is treated as a single host, and /31 as a 2-host point-to-point link (RFC 3021) with no separate network or broadcast address.

How many usable hosts are in a subnet?

For most subnets it is 2^(32−prefix) − 2, subtracting the network and broadcast addresses; /31 and /32 are special-cased.

IPv4 Subnet Calculator

Enter an IPv4 address and prefix to get the network and broadcast addresses, usable host range, host count, subnet mask, wildcard mask, CIDR, and IP class.

How to use IPv4 Subnet Calculator

Enter an IPv4 address.
Choose the CIDR prefix or subnet mask.
Read the network, broadcast, and host details.

Frequently asked questions

How are /31 and /32 handled?: /32 is treated as a single host, and /31 as a 2-host point-to-point link (RFC 3021) with no separate network or broadcast address.
How many usable hosts are in a subnet?: For most subnets it is 2^(32−prefix) − 2, subtracting the network and broadcast addresses; /31 and /32 are special-cased.

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