Calculate IP subnet information including network address, broadcast address, usable IP range, and subnet mask from CIDR notation.
Enter IP address
Type an IP address like 192.168.1.0 in the IP Address field.
Set CIDR prefix
Enter the subnet mask bits (0-32) or click a common subnet preset.
View subnet details
See network address, broadcast, usable IP range, and host count instantly.
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CIDR (Classless Inter-Domain Routing) notation is a compact way to specify IP address ranges. It uses a slash followed by a number (e.g., /24) to indicate how many bits are used for the network portion. For example, 192.168.1.0/24 represents 256 IP addresses from 192.168.1.0 to 192.168.1.255.
They represent the same information in different formats. A /24 CIDR equals subnet mask 255.255.255.0. The CIDR number indicates how many bits are '1' in the subnet mask. /24 means 24 ones followed by 8 zeros in binary.
/24 (256 addresses) is most common for small networks and home routers. /16 (65,536 addresses) is used for larger organizations. /32 is a single IP address. /30 (4 addresses, 2 usable) is common for point-to-point links between routers.