"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. For more developer tools, check our Developer Tools Guide.

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.

Practical Example: Office Network Planning

Suppose you're setting up a new office network and need to allocate IP ranges for different departments:

• HR Department: 192.168.10.0/26 (64 IPs, 62 usable)
• Engineering: 192.168.20.0/24 (256 IPs, 254 usable)
• Guest WiFi: 192.168.30.0/28 (16 IPs, 14 usable)

Our calculator shows you exactly how many devices can fit in each subnet, and what the usable IP range is.

Common Subnet Masks Quick Reference

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.

Why User-Agent Parsing Matters

1. Analytics: Understand what browsers your visitors use
2. Debugging: Identify if a bug is browser-specific
3. Compatibility: Check if your site works on mobile devices
4. Security: Detect suspicious or outdated browsers

Limitations of UA Parsing

• UA Reduction: Chrome now sends less detailed UA strings
• Spoofing: Some browsers fake their UA for compatibility
• Edge Cases: Rare browsers or crawlers may not be detected correctly

IP Info Lookup

Enter an IP address, get geolocation data, ISP information, and abuse contact.

Useful for:

• Checking where a visitor is from
• Identifying suspicious traffic
• Debugging CDN or geo-blocking issues

FAQ: Free Network Tools Online

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. Includes practical examples for office network planning.

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. Good for debugging browser-specific issues.

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. All processing is client-side for privacy.

What is CIDR and why use it?

CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses and routing. It replaces the old class-based system (Class A, B, C) with flexible prefix lengths (e.g., /24, /26). CIDR allows more efficient use of IP address space.

How to calculate usable hosts in a subnet?

Formula: 2^(32 - CIDR) - 2. For example, /24 has 2^(32-24) - 2 = 254 usable hosts. The -2 is because the network address and broadcast address are not usable for hosts.

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

For more networking tools, check our IP Subnet Calculator and IP Info Lookup.