IP / Subnet Calculator
Enter an IP address and subnet mask to calculate the network address, broadcast, host range and binary representation
What is a Subnet?
A subnet is a logical subdivision of an IP network into smaller, more manageable segments. Subnets allow more efficient IP address management, improve network security and reduce unnecessary broadcast traffic. Each subnet is identified by a network address and a subnet mask that together define the range of IP addresses belonging to that subnet.
CIDR Notation
CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and routing. The CIDR prefix (e.g. /24) specifies how many bits are used for the network portion of the IP address. The higher the prefix, the smaller the network and the fewer available hosts. For example, /24 means 254 hosts, /16 means 65,534 hosts, and /8 means over 16 million hosts.
IP Network Classes
| Class | Address Range | Prefix | Hosts |
|---|---|---|---|
A | 1.0.0.0 – 126.255.255.255 | /8 | 16,777,214 |
B | 128.0.0.0 – 191.255.255.255 | /16 | 65,534 |
C | 192.0.0.0 – 223.255.255.255 | /24 | 254 |
D | 224.0.0.0 – 239.255.255.255 | multicast | — |
E | 240.0.0.0 – 254.255.255.255 | reserved | — |
Subnet Calculator Use Cases
Network Planning
Designing network topology and dividing IP address space
Router Config
Setting static routes and network interface addresses
Diagnostics
Verifying that hosts belong to the same subnet
Security
Network segmentation and isolation of critical systems
VLSM / CIDR
Planning hierarchical IP address allocation
Documentation
Creating network infrastructure documentation