CIDR to IP Range Converter
Quickly find the start and end IP of any CIDR block.
What is CIDR Notation?
CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and IP routing. It replaces the old system based on classes (A, B, and C) and is used heavily by network administrators, cloud providers (like AWS or Azure), and firewall configurations.
1
Enter the Network
Type an IP address and a slash followed by a number between 0 and 32 (for IPv4) or up to 128 (for IPv6). Example: 192.168.1.0/24.
2
Convert
Click convert to instantly calculate the first usable IP, last usable IP, and total number of hosts in that subnet.
3
Apply to Firewalls
Use the resulting IP ranges to safely configure access control lists (ACLs), BGP peering, or AWS security groups.
Common CIDR Examples
/32- Represents a single IP address (1 host). Used for explicitly allowing/blocking one computer./24- The standard home network size. Provides 256 addresses. e.g., 192.168.1.0/24/16- A large enterprise network block containing 65,536 addresses./0- Represents the entire internet (any IP). Often seen in route tables as 0.0.0.0/0.