Subnet Calculator

WHAT IT DOES

Subnet Calculator is a floating panel that helps network administrators, developers, and IT students quickly compute subnet details. Enter an IP address and a subnet mask in CIDR notation (e.g., /24) or dotted decimal (e.g., 255.255.255.0)—the panel instantly calculates the network address, broadcast address, usable host range, total number of hosts, subnet mask in both formats, and the wildcard mask. A binary representation of the subnet mask is provided for educational purposes, making it easier to understand subnetting at the bit level. The panel supports both IPv4 and IPv6, with IPv6 mode showing expanded and compressed address formats, prefix length, and network range. You can insert the network address, broadcast address, or usable host range directly into any editable field on the page (input, textarea, or contenteditable) with one click, or copy all results to your clipboard. Perfect for network troubleshooting, configuration planning, certification study, or any IP subnetting task.

WHERE IT RUNS

The panel overlays any website that loads the BotGentz extension—whether you're on a cloud console, a network management tool, a documentation page, or any other web page. It works on all modern Chromium‑based browsers (Chrome, Edge, Brave, Arc) and Firefox. The script injects a self‑contained UI element that does not interfere with the host page's layout, styles, or JavaScript execution. It runs client‑side only, with no external API calls or cloud dependencies.

HOW TO USE

After installing the free BotGentz extension, visit any page and click the extension icon to activate the panel. The first time you use Subnet Calculator, it will appear as a draggable widget near the bottom‑right corner of your viewport. To calculate subnet details:

- Select IPv4 or IPv6 from the dropdown (default is IPv4).

- Enter an IP address (e.g., 192.168.1.0 for IPv4 or 2001:db8::1 for IPv6).

- Enter a subnet mask in CIDR notation (e.g., 24) or dotted decimal (e.g., 255.255.255.0) for IPv4; for IPv6, use CIDR only (e.g., 64).

The panel updates all calculations live—network address, broadcast address, usable host range, total hosts, subnet mask, wildcard mask, and binary representation. To use the results:

- Click "Insert Network Address" to paste the network address into the focused editable field.

- Click "Insert Broadcast Address" to paste the broadcast address into the focused field.

- Click "Copy All Results" to copy the network address, broadcast address, host range, total hosts, subnet mask, wildcard mask, and binary representation to your clipboard.

The panel remembers your last used IP address, subnet mask, and IP version across sessions.

BIT‑WISE SUBNET ENGINE WITH DUAL‑STACK IPV4/IPV6 HANDLING

Unlike simplistic calculators that rely on string parsing alone, this panel uses a bit‑wise subnet engine that treats IP addresses as 32‑bit (IPv4) or 128‑bit (IPv6) integers. For IPv4, the engine converts dotted‑decimal addresses to 32‑bit integers using bit shifts, then applies the subnet mask via bitwise AND to compute the network address. The broadcast address is calculated by ORing the network address with the bitwise NOT of the mask. The wildcard mask is derived as the inverse of the subnet mask. The engine also includes a CIDR‑to‑mask converter that handles both CIDR integers and dotted‑decimal masks, automatically detecting the input format. For IPv6, the engine expands compressed addresses to full 8‑group notation, computes the network prefix by applying the prefix length to each 16‑bit group, and displays both expanded and compressed forms. The binary representation module converts the subnet mask to an 8‑bit per octet binary string, providing a visual learning tool. The engine also calculates total host counts using 2^(32‑cidr) for IPv4 and 2^(128‑cidr) for IPv6, with special handling for /31 and /32 subnets where usable host counts differ.

THE PANEL

- Drag: Click and hold the panel's header bar to move it anywhere on the screen.

- Per‑site position: The panel stores its last position separately for each domain (e.g., different positions for AWS Console vs. Azure Portal) using the browser's localStorage, keyed by hostname.

- Snap: When dragged near any edge of the viewport, the panel snaps to that edge with a 16px margin for a clean, docked feel.

- Collapse: Click the "−" button in the header to collapse the panel to a compact title bar, preserving all current values. Click "+" to expand it back.

- Resize: Drag the bottom‑right corner handle to resize the panel from 280px to 600px wide and 200px to 500px tall; the layout adapts responsively.

- Escape: Press the Escape key while the panel is focused to close it entirely (you can reopen it from the extension toolbar).

PLEASE NOTE

This script requires the free BotGentz extension to run—it is not a standalone bookmarklet or user script. Websites frequently update their DOM structures and security policies; while we strive to keep the panel functional across thousands of sites, occasional updates may be needed. The calculator performs all operations entirely in your browser—no data is sent to any server, and no cookies or tracking identifiers are used. Your IP addresses and subnet data remain private to your local session and are persisted only via GM_setValue (the extension's local storage) for convenience, not shared across devices or sessions. IPv6 support is basic—it handles expanded/compressed addresses and prefix length calculations but does not include advanced features like subnetting into smaller blocks or detailed host range expansion. For production network planning, always verify calculations with official tools and documentation.