Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Home / Developer / IP Subnet Calculator

IP Subnet Calculator

IPv4 and IPv6 CIDR calculator, subnet splitter, range to CIDR and ULA generator.

Free, no uploads, no sign-up. Runs 100% in your browser.

How IP Subnet Calculator works

Addresses are handled as big integers, so IPv4 and IPv6 use the same exact math. You get network, broadcast, host range, masks, address type, reverse DNS and binary views.

How to use IP Subnet Calculator

Open IP Subnet Calculator and paste or type your input.
Results update instantly as you type.
Tweak options such as format, indentation or algorithm.
Copy the output or download it as a file.

Tips

Everything is computed locally. Safe for tokens, keys and private data.
Use Ctrl/⌘ + K to jump between developer tools quickly.

IP Subnet Calculator FAQ

Are my files uploaded?: No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
Is it free? Are there limits or watermarks?: Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
Does it work offline?: Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Related tools

MAC Address Lookup & Generator: Find the vendor of a MAC address offline, convert formats and generate random MACs.
Number Base Converter: Binary, octal, decimal and hex conversion.
JSON Formatter: Prettify, validate, minify and explore JSON as a tree.
QR Code Generator: QR codes for links, Wi-Fi, vCards and text with colors and logo.