AkousaCIDR Calculator
Calculate IP ranges, subnet masks, and host counts from CIDR notation.
About CIDR Calculator
The CIDR Calculator computes comprehensive subnet details from CIDR (Classless Inter-Domain Routing) notation — the standard format (e.g., 192.168.1.0/24) for specifying IP address blocks in network engineering, cloud infrastructure, and security policy configuration. Given any IPv4 or IPv6 CIDR block, it instantly calculates the network address, broadcast address, subnet mask (in dotted-decimal and binary), first/last usable host IPs, total host count, and wildcard mask. CIDR replaced the older class-based addressing system and is the foundation of all modern IP routing.
How to Use
Enter an IP address with CIDR prefix length (e.g., 10.0.0.0/8 or 172.16.0.0/12) into the input field. The calculator immediately displays all subnet parameters: network address, broadcast address, usable IP range, subnet mask, wildcard mask, total addresses, and usable hosts. Use the subnet splitter to divide a CIDR block into equally-sized smaller subnets.
Common Use Cases
- Planning IP address allocation and subnetting for new enterprise network deployments and data center infrastructure
- Configuring AWS VPC CIDR blocks, Azure VNet address spaces, and GCP subnetwork ranges for cloud infrastructure provisioning
- Writing firewall rules and security group policies by determining the exact IP range covered by a CIDR notation block
- Verifying whether a specific IP address falls within a given CIDR range for network access control and routing table analysis
- Subdividing a /16 or /8 block into department-specific /24 or /26 subnets for network segmentation and broadcast domain isolation