The CIDR/Netmask tool provides information about a CIDR range including the IP addresses and host addresses contained in it.
About this Tool
This tool provides the following IP information:
- IPv4 and IPv6 subnet netmask (including binary and decimal expressions)
- Number of networks and hosts available in each relevant CIDR range
- IP Classes (e.g., IPv4 A=/8, B=/16, C=/24, etc.)
- Netmask IP range and binary ip address
What is CIDR? Classless Inter-Domain Routing (CIDR) is an expansion of the IP addressing system that allows for a more efficient and appropriate allocation of addresses. CIDR changed fixed fields into variable-length fields, allowing addresses to be assigned with more granularity. The CIDR IP address includes a number that tells how the address is split between networks and hosts. For example, in the CIDR address 188.8.131.52/20 the /20 indicates that the first 20 bits are used for network ID and the remaining 12 (there are 32 bits in the IP address) are used for host ID.