CIDR Calculator
Simplify Your Network Planning
What is CIDR (Classless Inter-Domain Routing)?
Classless Inter-Domain Routing (CIDR) is a modern IP addressing scheme that improves the efficiency and scalability of network routing. Introduced in 1993 to combat IPv4 address exhaustion, CIDR replaced the rigid class-based system (Class A, B, and C) with a more granular and flexible approach using variable-length subnet masking (VLSM).
In CIDR notation, an IP address is followed by a slash ( / ) and a number that indicates the number of bits used for the network prefix (e.g., 192.168.10.0/24). This format enables precise control over IP address allocation, allowing ISPs and enterprises to:
Create subnetworks of any size based on actual needs
Reduce the size of routing tables by aggregating multiple routes (route summarization)
Maximize utilization of limited IPv4 space
Seamlessly transition and scale into IPv6 networks
CIDR also supports supernetting, allowing multiple contiguous networks to be represented as a single routing entry. This reduces the global BGP table size and improves internet backbone performance.
Ultimately, CIDR is foundational to modern internet architecture, enabling efficient IP address distribution, better routing control, and scalable network segmentation across enterprise, data center, and ISP environments.
Use the CIDR Calculator
Streamline complex IP planning with precision. The inoRain CIDR Calculator is engineered for network professionals who need fast, reliable, and accurate subnet calculations across IPv4 and IPv6 environments.
inoRain's tool delivers comprehensive outputs in real-time, including subnet masks, wildcard masks, total and usable IP ranges, network/broadcast addresses, and reverse DNS zones.
Simply input any IP address or CIDR block, and the calculator automatically resolves:
Network and host segmentation
Addressable IP count
First/last usable IP addresses
Binary and hexadecimal representations
Supernetting or subnetting options
Multicast and special-use address checks (where applicable)
Built with a dual-stack architecture and intuitive UX, the tool eliminates manual calculations and minimizes errors, empowering faster decision-making for complex network topologies.
Calculate CIDRBenefits of Using a CIDR Calculator
Precise subnet mask calculations
Optimal IP range utilization
Reduced risk of overlapping subnets
Efficient routing and address planning
Supports modern networking needs (IPv6)
Key Features of inoRain’s CIDR Calculator
Dual-stack support: Works with both IPv4 and IPv6
Instant results: Subnet mask, address count, wildcard, and range in real time
User-friendly interface: Built for speed and clarity
CIDR-to-IP and IP-to-CIDR conversion
Export and save results for documentation or audits
Privacy-first: No data stored or tracked
Who Benefits from inoRain’s CIDR Solutions
Network engineers and architects
ISP infrastructure teams
System administrators
Data center managers
IT departments of large enterprises
DevOps and cloud teams managing virtual networks
How It Works
inoRain’s CIDR Calculator is designed with a backend logic engine that parses and computes IP addressing details using binary-level operations, ensuring precise and standards-compliant results every time.
1
Input Parsing
Enter any valid IP address (IPv4 or IPv6) or a CIDR block (e.g., 10.0.0.0/22). The system validates the format and determines whether it's a host address or network range.
2
Prefix Analysis
The calculator identifies the network prefix length and applies bitwise operations to determine subnet boundaries, broadcast addresses (for IPv4), and host ranges.
3
Binary & Decimal Conversion
Each component — network address, subnet mask, wildcard mask, and usable range — is displayed in both binary and decimal form to aid in technical audits and low-level configuration tasks.
4
Address Space Calculation
Supernetting suggestions for route aggregation
Subnetting splits based on target prefix length or desired host count
Reverse DNS (PTR) record formatting
Classless vs. classful representation comparison
IPv6 compression/decompression for expanded readability
5
Output Delivery
Results are rendered in a clean, exportable format — ideal for configuration files, documentation, provisioning scripts, or NMS integration.