IP Subnet Calculator

Calculate subnet information for IPv4 and IPv6 addresses

IPv4 Subnet Calculator
Enter an IPv4 address and either a CIDR value or subnet mask to calculate subnet information.

Enter a number between 0 and 32

Enter either CIDR or subnet mask, not both

IPv4 Subnetting Explained
Understanding how IPv4 subnetting works

What is Subnetting?

Subnetting is the process of dividing a network into smaller networks called subnets. This helps with network organization, security, and efficient use of IP addresses.

Key Concepts

  • Network Address: The first address in a subnet, used to identify the subnet itself.
  • Broadcast Address: The last address in a subnet, used to send data to all hosts in the subnet.
  • Host Addresses: All addresses between the network and broadcast addresses that can be assigned to devices.
  • Subnet Mask: A 32-bit number that determines which part of an IP address is the network portion and which is the host portion.
  • CIDR Notation: A shorthand way to represent a subnet mask (e.g., /24 means 255.255.255.0).

Example

For the IP address 192.168.1.100 with a subnet mask of 255.255.255.0 (/24):

  • Network Address: 192.168.1.0
  • Broadcast Address: 192.168.1.255
  • Usable Host Range: 192.168.1.1 to 192.168.1.254
  • Total Usable Hosts: 254