FREE TOOLS / SUBNET CALCULATOR
Subnet Calculator
Calculate IPv4 address spaces and CIDR masks locally in your browser. Instantly see network address, broadcast address, and wildcard masks.
Security and Privacy Note:
This tool runs in your browser for preliminary assessment and calculation purposes. Data entered here is not sent to the server, stored or logged. Use sample or masked data instead of real production IP plans, hostname lists, configuration files or confidential network information. Results are not a design, security or resilience guarantee.
IP Planning & Security
Proper IP subnetting and segmentation forms the cornerstone of enterprise network security. When planning:
- Divide subnets based on business functions and trust levels.
- Isolate database groups and internal servers from external networks.
- Verify wildcard masks carefully when writing firewall rules and ACLs.
- Use /31 and /32 subnets only for point-to-point (P2P) links and loopback routing interface addresses.