Inputs
Results
Usable hosts—
Subnet mask—
Wildcard mask—
Network address—
Broadcast address—
Usable host range—
Total addresses—
IP class—
Type—
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Frequently Asked Questions
What is a subnet mask?
A subnet mask separates the network portion of an IPv4 address from the host portion. For example /24 equals 255.255.255.0, leaving 8 bits for hosts.
How many hosts are in a /24?
A /24 has 256 total addresses and 254 usable hosts; the network and broadcast addresses are reserved.
What is CIDR?
CIDR (Classless Inter-Domain Routing) writes the prefix length after the IP, e.g. 192.168.1.0/24, instead of fixed class-based masks.
What does /31 mean?
A /31 has only 2 addresses and, per RFC 3021, both are usable for point-to-point links. A /32 is a single host address.
Results are for IPv4 networks only and are provided for planning convenience. Always verify against your live configuration.