IPv4 Address to CIDR Notation
Converts IPv4 Address Range to CIDR Notation

This tool will convert an IPv4 address range into CIDR format. CIDR (Classless Inter-Domain Routing) format is a compact format of expression an IP address along with it routing information. A CIDR notation of is a representation of IPv4 addresses with the range of to To use this tool, enter two IPv4 addresses below in dotted format (e.g.,

IP - An IP (Internet Protocol) address is a unique identifier used in network communication. Network devices, such as a computer, a network printers and a router, all have a unique IP within their own network to enable you to print your document to your network, connect to a website, or play online games. An IP address is analogous to a phone number.

Special IP Address Blocks

These special addresses are IPs that are reserved for network testing and troubleshooting and are not assigned to devices.

  • - Reserved for self-identification.
  • - Reserved for loopback, testing and troubleshooting.
  • - Reserved for link local.
  • - Reserved for 6to4 Relay Anycast.
  • - Reserved for network interconnect device benchmark testing.
  • - Reserved for mulitcast addresses, which is an address which has multiple destinations.
  • - Reserved for future use.
  • - This is the last IPv4 address and is represents 'all' host. It is reserved as a limited broadcast destination address.

Reserved Private IP Address Block

The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of IP address space for private networks. These private IP addresses are typically used in local networks and cannot be accessed directly from a public network such as the Internet.

  • - (10/8 prefix)
  • - (172.16/12 prefix)
  • - (192.168/16 prefix

From IP:
To IP: