"Can you figure out why this subnet doesn't talk to that one?"

You could open a terminal and type ipcalc. Or you could use our subnet calculator if you're on a machine without that package. Craftisle's network tools cover three narrow but frequent needs.

IP Subnet Calculator

Input an IP and CIDR prefix (like 192.168.1.0/24), get back: network address, broadcast address, usable host range, total hosts, subnet mask in dotted decimal and hex.

Handles IPv4 only. No IPv6 support yet — IPv6 subnet math is different and isn't implemented in the current version.

If you're designing VLANs or planning address allocation for a new office network, this gives you the numbers in one view instead of doing the bit math by hand.

User-Agent Parser

Paste a user-agent string, get a structured breakdown: browser name and version, OS, device type (mobile/desktop/tablet), rendering engine.

Example input:

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 Chrome/131.0.0.0 Safari/537.36

Output: Chrome 131 on macOS, desktop, WebKit engine.

The parser uses a regex-based UA detection library. Modern browsers are increasingly freezing or faking their UA strings (Chrome's UA reduction), so the output is a best guess, not ground truth.

FAQ: Free Network Tools Online

Best free IP subnet calculator online?

Craftisle IP Subnet Calculator — input IP + CIDR (e.g. 192.168.1.0/24), get network address, broadcast, host range, total hosts. IPv4 only.

How to parse user-agent string free?

Use User-Agent Parser — paste UA string, get browser/OS/device type. Regex-based detection. Modern browsers fake UA strings, so output is best guess.

Free network tools no terminal needed?

Craftisle Network Tools run in browser — no need to install ipcalc or nmap. Good for quick checks on machines without dev tools.

Try the User-Agent Parser — paste your own browser's UA string and see what it reports.