Calculate a subnet from CIDR notation 12 uses
Get the network address, broadcast address, subnet mask, and usable host range for any CIDR block, in your browser.
/ 5 - Be the first to rate this tool Thanks for rating!
Verification failed - please try again.
Quick check
Please verify you're not a robot to submit your rating.
Give feedback
Tell us what you think about Calculate a subnet from CIDR notation.
- Network
- Broadcast
- Subnet mask
- First host
- Last host
- Usable hosts
- Runs entirely in your browser — your IP is never sent to a server
- Get the network address, broadcast address, mask, and usable host range
- Free, no account required
How it works
-
1
Paste the string, expression, or value you want to inspect.
-
2
It's parsed instantly and broken down on screen.
-
3
Review the details or matches highlighted for you.
-
4
Copy any part of the result you need.
Why use this tool
Every dev utility, one place
Format, convert, encode, decode, and generate — no more juggling ten tabs.
100% private, always
Every tool runs in your browser — your code and data are never sent anywhere.
Works on any device
Runs on Windows, Mac, Linux, iOS, and Android — nothing to install.
Instant results
No queues, no build step — results update as you type.
Built to handle real data
Full Unicode support and RFC-compliant parsing, edge cases included.
Free, always
Free to use, with no rate limits, sign-up, or trial period.
Frequently asked questions
It indicates how many bits of the IP address are strictly locked for the network routing identifier.
Yes, it subtracts the network and broadcast addresses to show exactly which IPs can be assigned to devices.
Yes, the math supports everything from a massive /1 down to a restrictive /32 single host.
The current engine is optimized purely for legacy IPv4 calculations.
Yes, the inverse wildcard mask is provided alongside the standard subnet mask.
From the blog
Mastering Base64: What It Is, How It Works, and When Not to Use It
Base64 is everywhere in modern web development, from data URIs to authentication headers. Here is a deep dive into how it works and common pitfalls to avoid.
Demystifying JSON: How to Troubleshoot Common Parsing Errors
JSON is the backbone of web APIs, but syntax mistakes can halt your code. Here is how to identify and fix missing commas, unescaped strings, and trailing characters.
Stop Pasting Secrets Into Random Websites: A Developer's Security Checklist
Every day developers paste API keys, JWTs, and credentials into online tools without a second thought. Here's why that habit is riskier than it seems, and a practical checklist to break it.
Recently viewed
Popular tools
Convert PDF to Excel for free
Pull tables and data out of a PDF into an editable spreadsheet.
Resize an image online for free
Resize JPG, PNG, or WebP images to exact dimensions or a percentage, right in your browser.
Compress a PDF file for free
Shrink PDF file size while keeping quality readable, right in your browser.
Convert PDF to Word for free
Turn a PDF into an editable Word document in seconds.
Convert JPG or PNG images to PDF for free
Combine one or more images into a single PDF document, right in your browser.
Merge PDF files online for free
Combine multiple PDF files into a single document in your browser. No install, no signup.
Generate a QR code for free
Create a static QR code for a URL, text, Wi-Fi, or contact card in seconds.
Generate a vCard QR code for free
Share your contact details instantly with a scannable vCard QR code.
Convert an image format for free
Convert between JPG, PNG, and WebP, right in your browser.
URL encode or decode a string online
Percent-encode or decode a URL or query string component instantly in your browser.
Format and validate JSON online
Paste JSON to pretty-print, minify, and validate it instantly in your browser.
Split a PDF into separate files for free
Extract pages or split a PDF into multiple files instantly in your browser.