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🏷️ IP Class Identifier

IP address classes are mostly obsolete in modern networking — CIDR replaced them in 1993 — but they still come up in textbooks, certification exams, and old documentation. This tool identifies the classical class of any IPv4 address and flags special ranges: RFC 1918 private space, loopback, link-local, multicast.

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Examples

Home router
Input192.168.1.1
OutputClass C · Private (RFC 1918)
Public web
Input142.250.190.46
OutputClass B · Public
Loopback
Input127.0.0.1
OutputClass A · Loopback
Multicast
Input224.0.0.1
OutputClass D · Multicast

Frequently asked questions

What are RFC 1918 ranges?

Private IP ranges usable freely on internal networks: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. Never routed on the public internet.

Are classes still used?

Not for routing — CIDR replaced them. Still show up in education and historical docs, and "Class A/B/C" remains a useful shorthand for subnet size.

About this calculator

IP Class Identifier runs entirely in your browser using standard formulas. No data is sent to any server. We don't share your inputs with lenders, brokers, or anyone else — there's no funnel and no follow-up email.

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Why this tool

vs typical free network-tools sites

NetToolsetTypical free site
PriceFreeFree
Signup requiredNoOften (for advanced features)
Ads inside the toolNoYes (banner + interstitial)
Logs your IP / queriesNoYes (often resold)
Data sent to a serverMath runs in browser; lookups hit Cloudflare DoH directlyYes (all goes through their server)
Open sourceYesNo
Bookmarkable URL per toolYesMixed
MultilingualEN / ES / PT / FR / DEUsually EN only
Loads in under 1sYes (static)Often slow (ad tracking)