About ITInsightHub

ITInsightHub is a collection of fast, free network engineering tools and references. No ads, no sign-up walls, no cookies.

Why we built this

Most online subnet calculators were built in a different era of the web. They hide results behind JavaScript that never renders for search engines and screen readers, they can't share a result as a link, they ignore IPv6 or RFC edge cases, and they bury the answer under advertising.

We think a reference tool should be fast, linkable, correct, and readable on any device. Every page here is pre-rendered server-side, every calculation produces a shareable URL, and the math follows the RFCs — including /31 point-to-point links (RFC 3021), /32 host routes, and proper handling of private, CGNAT and documentation ranges.

What you'll find here

• IPv4 subnet calculator — network, broadcast, host range, wildcard mask and binary breakdown.
• IPv6 subnet calculator — expand/compress addresses, analyze prefixes.
• Wildcard mask calculator — CIDR ⇄ inverse masks for ACLs.
• IP range to CIDR converter — minimal covering blocks, with batch mode.
• VLSM calculator — plan right-sized subnets from host counts.
• Subnet cheat sheet — every mask from /0 to /32, printable.
• Per-mask reference pages — deep dives for each prefix length.

How it's built

The entire site runs on Cloudflare Workers at locations around the world, so pages render close to you in milliseconds. Tools work even with JavaScript disabled; when JavaScript is available, results update live as you type.

Accuracy policy

All calculations are unit-tested against known-good vectors. If you spot an error anywhere, it will be fixed quickly — accuracy matters more than anything else on this site.