IP / CIDR‑Validator

IP / CIDR Validator - IPv4, IPv6 & Prefix Length

IP addresses and CIDR notation identify hosts and networks. This page validates IPv4, IPv6, and prefix lengths with numeric checks to catch common mistakes.

What is CIDR?

Classless Inter‑Domain Routing expresses a network as an address plus a prefix length—/24 for IPv4 or /64 for IPv6. The prefix indicates how many leading bits form the network portion.

How validation works

IPv4 segments must be 0–255 without leading zeroes. IPv6 supports eight hex groups with optional :: compression. For CIDR, the prefix length must be within 0–32 (IPv4) or 0–128 (IPv6).

About this validator

The goal is correctness with clear feedback, not full subnet math. For network planning, pair this with tools that compute ranges, masks, and broadcast addresses.

Accurate input prevents routing and security errors. Validate early and use authoritative libraries in back‑end services.