About NetCalcTools

NetCalcTools is a free, growing collection of tools and guides for network engineers, students, system administrators, and anyone who works in networking or IT. The goal is simple: give you accurate results instantly, without ads getting in the way, without a login wall, and without unnecessary clutter.

Why we built this

Most online tools are either buried in ads, hidden behind sign-up walls, or built on outdated interfaces that are painful to use on a phone. We wanted tools that are fast, accurate, accessible, and genuinely pleasant to use, whether you're studying for a CCNA exam, configuring a VLAN, generating a secure password, or double-checking a CIDR range at 2 AM.

What's available today

• IP Subnet Calculator: IPv4 and IPv6 subnetting with network and broadcast addresses, usable host range, subnet and wildcard masks, CIDR notation, and a full IPv4 reference table from /1 to /32.
• Wildcard Mask Calculator: convert between prefix lengths, subnet masks, and the wildcard masks used in Cisco ACLs and OSPF network statements.
• Password Generator: cryptographically random passwords and passphrases with a live strength meter.
• DNS Lookup: A, AAAA, CNAME, MX, TXT, NS, SOA and CAA records, compared across the Cloudflare and Google public resolvers.
• What Is My IP: your public IPv4 and IPv6 address, ISP, approximate location, and browser details.
• MAC Address Lookup: find the manufacturer behind a MAC address using the IEEE registry.

The Guides section explains the ideas behind the tools, from subnet masks and private IP ranges to the commonly used /24, /27 and /16 networks. More tools and guides are on the way.

Accuracy & privacy

The subnet calculator, wildcard mask calculator, password generator, and MAC address lookup run entirely in your browser. What you type into them is never sent to our servers. Two tools work differently because they have to: DNS Lookup sends the domain you enter to the public DNS-over-HTTPS resolvers run by Cloudflare and Google, and What Is My IP contacts third-party IP lookup services to find your public address and approximate location. NetCalcTools does not store the results of either tool. The Privacy Policy explains this tool by tool.

Technical accuracy matters more than anything else on this site. If you find a wrong value, a misleading explanation, or an edge case a tool gets wrong, please tell us and we will correct it.

Who runs NetCalcTools

NetCalcTools is an independently run project, built and maintained by the NetCalcTools team and improved continuously based on real user feedback.

Ads and funding

NetCalcTools currently shows no advertising and no affiliate links. If that ever changes, sponsored or affiliate content will be clearly labeled as such, and the Privacy Policy will be updated before it goes live.

Get in touch

Found a bug, spotted an error, or have a feature request? Email us at hello@netcalctools.com. We read every message.