IP Address Lookup

Validate and analyze an IPv4 or IPv6 address right in your browser — no network calls.

ToolsSoup's IP Address Lookup is a free online IP validator and analyzer that runs entirely in your browser. Paste any IPv4 or IPv6 address and instantly see whether it is valid, which version it is, its decimal, hexadecimal, and binary forms, its class and type (private, public, loopback, link-local, multicast, reserved, and more), and its reverse-DNS PTR name. Everything is computed locally — nothing is ever sent to a server.

What does this IP address lookup tool do?

This is an offline IP address validator and analyzer, not a geolocation service. It checks that an address is well-formed and then breaks it down. For IPv4 it shows the 32-bit integer value, the hexadecimal and dotted-binary representations, the address class (A, B, C, D, or E), whether the address is private (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), loopback (127.0.0.0/8), link-local (169.254.0.0/16), multicast, or reserved, and the in-addr.arpa reverse-DNS name. For IPv6 it shows the fully expanded and compressed forms, classifies the address as loopback (::1), unspecified (::), link-local (fe80::/10), unique-local (fc00::/7), multicast (ff00::/8), or documentation (2001:db8::/32), and builds the ip6.arpa reverse-DNS name.

How to look up an IP address

Analyzing an address takes a couple of seconds:

  1. Type or paste an IPv4 or IPv6 address into the box. You can append a /prefix (for example 192.168.0.0/24) to also see the CIDR network.
  2. Click Analyze, or just press Enter.
  3. Read the breakdown: version, type, scope, numeric forms, and the reverse-DNS PTR record.

Why use this IP address tool?

  • Validates both IPv4 and IPv6, including compressed and IPv4-mapped IPv6 forms.
  • Shows decimal, hexadecimal, and binary representations of IPv4 addresses.
  • Identifies private, loopback, link-local, multicast, reserved, and public ranges.
  • Generates the reverse-DNS PTR name (in-addr.arpa / ip6.arpa) for any address.
  • Runs 100% in your browser with no network requests, so it works offline and keeps your data private.

Frequently asked questions

Does this tool show the geographic location of an IP?

No. Geolocation requires querying an external database over the network, which this static tool deliberately does not do. Instead it analyzes the address itself — its version, numeric forms, class, type, and reverse-DNS name — entirely on your device.

What makes an IP address private?

RFC 1918 reserves three IPv4 ranges for private networks: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Addresses in these ranges (like 192.168.0.1) are used inside home and office networks and are not routable on the public internet. IPv6 uses the unique-local range fc00::/7 for a similar purpose.

What is a loopback address?

A loopback address always refers to the local machine itself. In IPv4 the whole 127.0.0.0/8 block is loopback (commonly 127.0.0.1), and in IPv6 it is the single address ::1.

What is the reverse-DNS PTR name?

A PTR record maps an IP address back to a hostname. The tool builds the special reverse-lookup name an address would use: octets reversed under in-addr.arpa for IPv4, and nibbles reversed under ip6.arpa for IPv6.

Can I analyze a subnet in CIDR notation?

Yes. Append a prefix length such as /24 to an IPv4 address and the tool will also show the network address for that CIDR block. IPv6 addresses accept a prefix up to /128.