CIDR Notation Calculator

Our CIDR Notation Calculator is a comprehensive networking tool designed for network engineers, system administrators, and developers. CIDR (Classless Inter-Domain Routing) is the modern standard for specifying IP address ranges and has replaced the older classful addressing system.

Key features: Convert CIDR notation to subnet masks and vice versa, calculate network and broadcast addresses, determine the range of usable IP addresses, identify IP class and whether an address is public or private, split large networks into smaller subnets (subnetting), and aggregate multiple CIDRs into a supernet (route aggregation).

How to use: Enter a CIDR notation (like 192.168.1.0/24) or a subnet mask to instantly see all calculated values. Use the Split CIDR section to divide a network into smaller subnets, or the Aggregate section to combine multiple networks. The reference table provides a quick lookup for all common CIDR prefixes from /8 to /32.

Common use cases: Planning network allocations, configuring firewalls and access control lists (ACLs), setting up VPCs in cloud environments (AWS, Azure, GCP), troubleshooting routing issues, and understanding IP address assignments in enterprise networks.