Subnet / CIDR Calculator
Calculate IP subnet mask, network address, broadcast address, IP range, wildcard mask, and usable host count from IP and CIDR prefix.
IP Subnet Mask & Network Range Calculator
Calculate IPv4 network boundaries, wildcard masks, and total usable hosts instantly. Works offline in your browser for DevOps, sysadmins, and network engineers.
Technical Specifications & Architecture
- Execution Environment:
- 100% Client-Side Browser Sandbox
- Data Privacy:
- Zero Server Storage / No Tracking
- Processing Speed:
- Real-time local CPU execution
- Cross-Platform:
- Works on Windows, macOS, Linux, iOS & Android
Local Processing for Network Tools
This tool runs within your browser sandbox using modern Web APIs. Inputs are processed on your local device CPU, avoiding network latency and ensuring your data is never stored on external servers or accessible to third parties.
Provide Input
Enter, paste, or upload your data into the input field above.
Configure & Process
The tool immediately processes your input in real time according to your chosen settings.
Copy or Save
Use the Copy button to copy the output to your clipboard, or download the result to your device.
Common Use Cases
- Design VPC and subnet ranges in AWS, Google Cloud, or Azure
- Calculate usable IP addresses for DHCP pools and router configuration
- Verify wildcard masks for Cisco ACLs and firewall rules
- Convert CIDR notation (/27, /28) to dotted decimal subnet masks (255.255.255.224)
You might also like
Connected Tools & Next Steps
Recommended developer utilities frequently used before or after Subnet / CIDR Calculator
My IP & Browser Info
View your public IP, user agent, language, screen size. Rate limited for fair use.
Browser Info
View browser capabilities: user agent, screen, language, connection type, cookies. All client-side, no server.
Request Headers Echo
See what headers your browser sends. Useful for debugging and API development. Shows all incoming request headers.
Other Network Tools
My IP & Browser Info
View your public IP, user agent, language, screen size. Rate limited for fair use.
Browser Info
View browser capabilities: user agent, screen, language, connection type, cookies. All client-side, no server.
Request Headers Echo
See what headers your browser sends. Useful for debugging and API development. Shows all incoming request headers.
HTTP Headers Checker
Fetch a URL and view response status and headers. Check CORS, cache-control, and server headers.
Frequently Asked Questions
- What is a CIDR notation?
- CIDR (Classless Inter-Domain Routing) notation specifies an IP address and its associated network prefix length (e.g. /24). The prefix number indicates how many leading bits are used for the network ID.
- How many usable hosts in a /24 subnet?
- A /24 subnet provides 256 total IP addresses, of which 254 are usable for hosts (excluding the network address .0 and broadcast address .255).
- What is the difference between Subnet Mask and Wildcard Mask?
- A Subnet Mask uses 1s for the network portion (e.g. 255.255.255.0). A Wildcard Mask is the bitwise inverse (e.g. 0.0.0.255), commonly used in Cisco ACLs and OSPF routing.
- Is my IP data sent to any server?
- No — all subnet calculations are performed entirely in your browser using local JavaScript.