CIDR Calculator

Calculate IP range, netmask, and more from a CIDR block.

How to use CIDR Calculator

  • Enter a CIDR block (e.g., 10.0.0.0/16) in the input field.
  • Click the 'Calculate' button.
  • View detailed network information including IP range and netmask.

About CIDR

What is CIDR?

Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and for IP routing. It replaces the older system based on classes A, B, and C.

CIDR Notation

CIDR notation consists of an IP address, a slash ('/'), and a decimal number. The number is the count of leading 1-bits in the routing prefix mask.

Features

  • Calculate Netmask
  • Identify First and Last IPs
  • Count Total Usable Hosts

Applications

  • Network planning
  • Subnetting
  • Firewall configuration