CalculatorsLesson 149Free preview
IP Subnet Calculator
This lesson is part of Web Developer Tools · All levels
Summary
IP Subnet Calculator calculates the details of a subnet from the IP address and CIDR prefix, such as network address, broadcast address, range of usable hosts, subnet mask, and number of hosts. The prefix shows how many bits are used for the network part, so/24 leaves 8 bits for the host. These calculations are important when designing local area networks, firewalls, or VLAN partitions.
Key points
- IPv4 is made up of 32 bits and written as four octets
- Prefix /n specifies n bit network and 32-n bit host
- Network addresses and broadcasts cannot be used by regular hosts
- The number of usable hosts = 2^(32-n) - 2 for prefix/30 down
- Private addresses: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16
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