CIDR / Subnet Calculator
Enter a CIDR block and get network address, broadcast, usable host range, wildcard mask, and subnet size — all computed locally.
Build Software with The Network Knife
Network engineering tools that work without a network
You need to build software. Developer utilities — offline, forever. The Network Knife delivers 6 purpose-built tools in a single HTML file.
The Network Knife packages six essential network engineering utilities into a single HTML file. Calculate subnets, plan VLSM allocations, inspect MAC addresses, convert IP addresses to binary, look up HTTP status codes, and reference well-known ports — all without an internet connection. Because the best network tools shouldn't require one.
WHAT'S INSIDE
6 tools in a single HTML file
IP Binary Viewer
Convert IPv4 addresses to binary with colour-coded octets. See exactly which bits belong to the network and which to the host.
MAC Address Inspector
Paste a MAC address and identify the vendor (OUI lookup), format it in common notations, and check if it's unicast, multicast, or locally administered.
VLSM Architect
Plan Variable Length Subnet Mask allocations from a base network. Enter subnet requirements and get an optimised, non-overlapping allocation plan with waste analysis.
HOW IT WORKS
Three steps. No setup.
1
Download the file
Purchase The Network Knife and download a single HTML file. No installer, no account, no setup.
2
Open in any browser
Double-click to open in Chrome, Firefox, Safari, or Edge. Works on any operating system.
3
Start working
Your data stays in your browser's local storage. Nothing is uploaded. Ever.
COMPLIANCE & GEOGRAPHY
Global
Works in any country. No server dependency, no regional restrictions.
FAQ
Frequently Asked Questions
How does The Network Knife help me build software?
The Network Knife provides 6 interconnected tools for developer utilities — offline, forever. CIDR calculator, IP binary viewer, MAC inspector, VLSM architect, HTTP status codes, and port reference. The irony: network tools that don't need a network.
Do I need an internet connection to build software with The Network Knife?
No. The Network Knife runs entirely in your browser as a single HTML file. All 6 tools work offline.
What is the difference between The Network Knife and cloud-based alternatives?
Cloud tools store your data on external servers, require subscriptions, and stop working without internet. The Network Knife is a one-time purchase ($39) that runs locally. Your data never leaves your device.
Can I use The Network Knife on multiple devices?
Yes. Once purchased, you can use The Network Knife on any device with a web browser. Copy the HTML file to as many devices as you need.
No cloud One fileOne-time purchase
Get The Network Knife — $39Sovereignty as a Service