What does a subnet calculator do?

A subnet calculator derives the network address, broadcast address, usable host range, subnet mask and number of addresses from an IP address and a prefix (CIDR) – for both IPv4 and IPv6.

What does the CIDR notation (e.g. /24) mean?

The number after the slash indicates how many bits belong to the network. /24 means 24 network bits and 8 host bits, i.e. 256 addresses (254 usable hosts) in the network.

What is the subnet mask?

The subnet mask separates the network part from the host part of an IP address. /24 corresponds to the mask 255.255.255.0, for example. IPv6 uses the prefix length instead.

IP Subnet Calculator – IPv4 and IPv6

Enter an IPv4 or IPv6 address with prefix, e.g. 192.168.1.0/24 or 2001:db8::/32.

IPv4 Examples

192.168.1.0/24 Home network

10.0.0.0/8 Class A private

172.16.0.0/12 Class B private

192.168.1.0/28 Small subnet

IPv6 Examples

2001:db8::/32 Documentation

fc00::/7 Unique Local

fe80::/10 Link-Local

2001:db8::/64 Typical LAN

My IP Subnet IP Lookup IPv4 Detail IPv6 Detail

IPv4 and IPv6 Subnet Calculator

The subnet calculator supports both IPv4 (CIDR /0–/32) and IPv6 (CIDR /0–/128). Simply enter the IP address – the tool automatically detects whether it is IPv4 or IPv6. For IPv4, the network address, broadcast, first and last host, subnet mask, wildcard mask and possible subnets are calculated. For IPv6, the network address, prefix length and address type are shown.