NetEng Sidekick: Subnet Calculator

Professional IPv4/IPv6 Subnet Calculator. Supports CIDR, Export, and VLSM.

NetEng Sidekick - Offline Subnet Calculator 🛑 Stop switching tabs during critical maintenance windows. 🖥️ Created by a network engineer for network engineers. NetEng Sidekick is the workflow accelerator designed specifically for Wired and Wireless Network Engineers, Sysadmins, and Cloud Architects. It moves the subnet calculator from a browser tab to a permanent Side Panel—keeping your calculations visible while you configure Wireless LAN Controllers, audit Firewall ACLs, or design Cloud VPCs. 🚀 Why this is your new favorite tool: 1. Always-On Side Panel 🖥️ Never lose your place again. Whether you are scrolling through a Cisco CLI session in a browser terminal or reading Azure documentation, your calculator stays open and ready on the right side of your screen. 2. Serious IPv6 Power 🌐 IPv6 isn't the future; it's the now. While other calculators fail at 128-bit math, NetEng Sidekick handles full IPv6 precision. Calculate Prefix Delegations for ISP handoffs. Visualize /64 breakdowns for IoT VLANs. Get accurate Range Start/End for massive address blocks without crashing your browser. 3. Smart Input (Cisco & Legacy Friendly) 🧠 We know the real world isn't always CIDR. Paste standard CIDR: 192.168.10.1/24 Paste legacy masks: 192.168.10.1 255.255.255.0 We handle both automatically. No toggles required. 4. Visual VLSM Breakdown 🍰 Need to carve up a /24 Management VLAN into smaller chunks for different building wings? Select your new mask size (e.g., /27). Instantly see a table of every available subnet. Click to copy the Network ID or Broadcast address instantly. 5. One-Click Efficiency ⚡ Every result is clickable. Copy the First Usable IP for your Gateway configuration or the Wildcard Mask for your OSPF config with a single click. 6. Export for Documentation 📄 [NEW] Done with your design? Export your calculation results to a .txt file instantly. Perfect for attaching to Change Management requests, Jira tickets, or saving to your project documentation folder. 🛠️ Built for the Daily Life of a Network Engineer WIRELESS ENGINEERS: Quickly calculate subnet sizes for Guest WiFi pools to ensure you don't run out of DHCP leases during peak hours. Verify AP Management subnets when deploying new controllers. WIRED ENGINEERS: Rapidly verify if a specific IP falls inside a Summary Route or ACL object group without leaving your monitoring dashboard. SECURITY TEAMS: Double-check CIDR ranges when whitelisting IP blocks in your WAF or Firewall to prevent accidental over-exposure. NETWORK ARCHITECTS: Plan complex VLSM schemas and export the plan to text files to share with the implementation team. 🔒 Privacy First 100% Client-Side: No data ever leaves your browser. Offline Ready: Works perfectly in air-gapped environments or when the internet is down (which is usually when you need it most!). Upgrade your workflow today. Add NetEng Sidekick to Chrome.