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Calculate CIDR network information including subnet mask, network address, broadcast address, and usable IP ranges
CIDR Calculator is a tool that calculates network information based on CIDR (Classless Inter-Domain Routing) notation. It accepts CIDR format (192.168.1.0/24) and provides subnet details. CIDR is a method for representing IP addresses and network sizes compactly, where the prefix length (/24) indicates the number of network bits. Information calculated: Network address (first IP of subnet), Broadcast address (last IP of subnet), Subnet mask (decimal and binary), Usable IP range (first-last usable), Total IPs (2^host bits), Usable hosts (total - 2), Wildcard mask. Key features: CIDR ↔ subnet mask conversion, Automatic network calculation, IP range display, All notation support, Real-time calculation. Use cases: Network planning (determine subnet sizes), Routing configuration (network routes), IP allocation (identify available IPs), Firewall rules (define network ranges), Subnet design (divide networks), Education (learn CIDR and subnetting). CIDR examples: /24 = 256 IPs, /16 = 65536 IPs, /8 = 16 million IPs. This tool calculates locally in your browser without uploading data.
CIDR calculator computes network properties from CIDR notation (IP/prefix): network address, broadcast address, subnet mask, wildcard mask, usable host range, and total addresses. Calculations use binary operations. The tool handles prefix validation, IP address validation, and automatic calculations.
CIDR enables VLSM creating subnets of different sizes from single network block. The tool assists subnet planning, calculating required prefix for host count, visualizing IP allocation, and preventing overlaps. Common applications include network design, IP planning, router configuration, and firewall rules.
IPv6 CIDR uses 128-bit addresses with /64 standard subnet size. The calculator handles IPv6 notation, prefix delegation, and address planning. Applications include network documentation, troubleshooting, capacity planning, and security. The tool provides both IPv4 and IPv6 calculations.
Calculate network address, broadcast, usable range from CIDR
Convert between IP/mask and CIDR notation freely
Detailed subnet statistics and binary representation
Support CIDR, dotted decimal, and binary formats
Plan and allocate IP subnets for different departments, floors, or locations within an enterprise network. Use CIDR calculator to determine optimal subnet sizes, prevent IP conflicts, and document network topology for IT teams.
Plan VPCs and subnets in cloud platforms like AWS, Azure, GCP. Calculate CIDR blocks to allocate private IP space, ensure no overlap between different VPCs, and optimize cloud resource network configuration.
When configuring firewall rules, precise network ranges are needed. Use CIDR calculator to determine IP address ranges to allow or deny, creating accurate access control lists (ACL) and security policies.
Design networks for container platforms like Docker and Kubernetes. Calculate Pod network CIDR, service network ranges, and node subnets to ensure proper container communication and network isolation configuration.
CIDR (Classless Inter-Domain Routing) notation represents IP address and subnet mask as single value (e.g., 192.168.1.0/24), where /24 indicates mask bits.
Count the number of consecutive 1 bits in subnet mask. For 255.255.255.0 (binary: 24 ones), CIDR is /24. Tool automates this conversion.
/24 has 256 IPs (254 usable), /25 has 128 IPs (126 usable). Each increment halves the subnet size. Use calculator to compare.
/24 subnet has 256 total IPs, 254 usable (excluding network and broadcast addresses). Tool shows exact calculation for any CIDR.
Private ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. Tool detects and identifies private addresses automatically.
CIDR address allocation specification
IPv4 subnetting guide and calculator
IPv4 subnet allocation tables
Subnet mask reference and conversion guide
Official IPv4 address space registry
Open the tool to try these features.