About Subnet Desk

Last updated 2026-10-13

Subnet Desk is a free set of IP addressing tools for network engineers, IT administrators and students working towards networking certifications. Each page does one job — a subnet, a CIDR block, an IPv6 prefix, a MAC address vendor — and works straight away: there is no account and nothing to install.

Every calculator shows how the answer was reached, usually in binary as well as dotted decimal, so you can check it against your own working or an exam answer.

How it works

• Everything runs in your browser. What you type or choose stays on your device; nothing is uploaded.
• Results are computed, not typed in. The worked examples on each page are produced by the same code the calculator runs.
• Checked against reference implementations. Each calculator has automated tests whose expected values come from Python’s standard ipaddress module or from the examples in the RFCs that define the addresses (RFC 4632 for CIDR, RFC 1918 for private ranges, RFC 4291 and RFC 5952 for IPv6).
• MAC vendor data comes from the IEEE Registration Authority public listing; see the credits page.
• Third-party material used on the site is listed on the credits page.

If a tool gives a wrong result, please tell us through the contact page.

Who runs it

Subnet Desk is owned and operated by the Subnet Desk team. You can write to us at support@dianqi188.com.

Advertising

The site is free to use. We may show advertising in future to pay for hosting and development. If we do, ads will be labelled “Advertisement”, will never cover a tool, and are described in the privacy policy.