About SubnetSolver

Last updated: May 2026

What is SubnetSolver?

SubnetSolver is a free, browser-based IPv4 and IPv6 subnet calculator. All calculations run entirely in your browser using JavaScript — no data is ever sent to a server. There is no login, no account, and no tracking of your calculations.

Who is it for?

SubnetSolver is built for:

• Network engineers — designing LANs, WANs, and data centre networks
• Cloud architects — planning AWS VPC, Azure VNet, and GCP VPC subnet ranges with accurate cloud-provider IP reservations
• DevOps and platform engineers — configuring Kubernetes CNI ranges, EKS node groups, and multi-AZ subnet splits
• Students — preparing for CCNA, CompTIA Network+, and other networking certifications
• System administrators — anyone who needs fast, accurate subnet calculations without installing software

What can it do?

• IPv4 subnet calculator — mask, wildcard, network, broadcast, host range
• IPv6 subnet calculator — prefix expansion and host range
• VLSM planner — variable-length subnet masking for multi-tier network design
• Subnet splitter — divide any CIDR block into equal sub-prefixes
• CIDR conflict checker — identify overlapping subnet ranges
• Cloud mode — AWS, Azure, and GCP reserved IP adjustments applied automatically
• CSV export — download subnet tables for documentation
• Shareable URLs — share a specific calculation with a colleague via URL

Why we built it

SubnetSolver was built because existing tools were either cluttered with ads before useful content, required sign-ups, or did not account for cloud provider IP reservations. A network engineer designing an AWS VPC needs to know that a /28 gives 11 usable hosts — not 14. We wanted a fast, clean, accurate tool that a network engineer could bookmark and actually rely on.

How accurate is it?

All subnet calculations follow RFC 950 (subnetting), RFC 1918 (private address space), and RFC 4632 (CIDR) standards. Cloud provider IP reservation counts are based on current AWS, Azure, and GCP documentation:

• AWS: reserves 5 IPs per subnet (.0, .1, .2, .3, .255)
• Azure: reserves 5 IPs per subnet (.0, .1, .2, .3, .255)
• GCP: reserves 4 IPs per subnet (.0, gateway, second-to-last, .255)

Privacy

SubnetSolver collects no personal data. Your calculation history is stored only in your browser's localStorage and never leaves your device. We use Google AdSense for advertising, which may use cookies to serve relevant ads. See our Privacy Policy for full details.

Contact

Questions, feedback, or bug reports: amrrehmandin@gmail.com