Subnet CIDR Pro

Subnet CIDR Pro is a clean, lightning-fast, and precise IPv4 subnet calculator and visual VLSM planner designed for network engineers, sysadmins, cloud architects, and IT students. Built natively for iOS with a focus on speed and clarity, it eliminates the guesswork from IP allocation and network boundary calculations. Whether you are configuring router interfaces in the datacenter, planning VPC subnets in AWS/Azure, or studying for Cisco CCNA/CCNP certifications, Subnet CIDR Pro delivers instant, accurate results. KEY FEATURES: 1. Instant IPv4 & CIDR Calculation • Real-time calculations as you type IP address or adjust CIDR prefix (/0 to /32). • Full breakdown: Subnet Mask, Wildcard Mask, Network Address, Broadcast Address, First/Last Usable Host, and Total Usable Hosts. • RFC 3021 Compliant: Correct handling for /31 point-to-point links (2 usable hosts) and /32 single host routing. • Binary Visualization: Clear binary breakdown highlighting network and host bit boundaries. • One-tap copying for any calculated value or complete CIDR summary. 2. Visual VLSM Subnet Planner • Automatically allocate Variable Length Subnet Masks (VLSM) from any parent IPv4 block. • Add custom subnet requirements with host counts and descriptive names. • Optimal subnet block sorting to eliminate IP space fragmentation. • Detect allocation overflows and subnet overlaps instantly. • Export or copy your complete allocation table with one tap. 3. Complete CIDR & Mask Reference • Interactive /0 to /32 quick-lookup cheat sheet. • Displays subnet masks, wildcard masks, total addresses, and usable host counts at a glance. • Instant search to quickly verify subnet boundaries. PROFESSIONAL & PRIVACY-FIRST: • 100% Offline & Self-Contained: All calculations run locally on your device. • Zero Ads & Zero Tracking: No analytics, no third-party SDKs, and no telemetry. • No In-App Purchases & No Subscriptions: One-time purchase unlocks lifetime complete access. • Native Dark Mode UI optimized for field diagnostics and server room environments. LEGAL & PRIVACY: • Privacy Policy: https://subnet.opshome.run/privacy/ • Terms of Use: https://subnet.opshome.run/terms/ • Support & Feedback: https://subnet.opshome.run/support/ Designed with pride by OpsHome for network practitioners who value precision, simplicity, and privacy.