Description
NetEng Sidekick - Offline Subnet Calculator
π Stop switching tabs during critical maintenance windows.
π₯οΈ 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 Panelβkeeping your calculations visible while you configure Wireless LAN Controllers, audit Firewall ACLs, or design Cloud VPCs.
π Why this is your new favorite tool:
1. Always-On Side Panel π₯οΈ 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 π 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) π§ 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 π° 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 β‘ 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 π [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.
π οΈ 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.
π 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.
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Details
| Version | 1.4.2 |
| Updated | Dec 9, 2025 |
| Size | 17.52KiB |
| First Seen | Mar 28, 2026 |
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