IPv4 CIDR Calculator

CIDR (Classless Inter-Domain Routing) calculators are simple tools to assist you to calculate a block of IP addresses. RFC-4632,   RFC-791 .



IP Range Information
CIDR / Bitmask
Network IP
Broadcast IP
First Host IP
Last Host IP
IP Class (Info)
Subnet Information
Netmask Wildcard
Number Of Host IPs
Total Number Of IPs

What is CIDR notation according to Wikipedia

CIDR notation is a compact representation of an IP address and its associated routing prefix. The notation is constructed from an IP address, a slash ('/') character, and a decimal number. The number is the count of leading 1 bits in the subnet mask. Larger values here indicate smaller networks. The maximum size of the network is given by the number of addresses that are possible with the remaining, least-significant bits below the prefix.

The IP address is expressed according to the standards of IPv4 or IPv6. The address may denote a single, distinct interface address or the beginning address of an entire network. The aggregation of these bits is often called the host identifier.

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