About IP Address Validator
IP Address Validator decides whether a string is a valid IPv4 or IPv6 address and tells you which it believes it is. For IPv4 it checks the familiar four-groups-of-digits shape and confirms that every group falls between 0 and 255, which correctly rejects entries such as 256.1.1.1 or 192.168.1. A string made of hex characters and colons is reported as IPv6.
That second test is deliberately permissive, and it is worth understanding before you rely on it. Rather than fully parsing the IPv6 grammar — compression with double colons, embedded IPv4 tails, zone identifiers and the eight-group limit — it simply checks that the input contains only hex digits and colons and includes at least one colon. A loosely formed string such as three colons in a row can therefore be reported as valid IPv6 when a strict parser would reject it.
So the tool is a quick triage that reliably separates IPv4 from IPv6 and catches range errors in IPv4. For IPv6, treat its verdict as a hint; if the address is destined for code or a configuration file, validate it with a strict parser as well.
How to use IP Address Validator
- 1 Paste the address into the field.
- 2 Read which version was detected, or that the input is not a valid address.
- 3 For an IPv6 result, confirm it with a strict parser before using the address in code.
Frequently asked questions
Why does it reject 192.168.1.256?
Because each of the four groups must fall between 0 and 255, and 256 is out of range. Every group is range-checked rather than just shape-checked, so out-of-range values are caught.
Is the IPv6 check reliable?
Not fully. It is a permissive test that only requires hex digits, colons and at least one colon, so it does not enforce the stricter rules of IPv6 syntax. Treat a positive result as a hint and validate strictly elsewhere when it matters.
Can it tell public addresses from private ones?
No. It reports validity and version only. There is no classification into private, loopback, link-local or reserved ranges, so 192.168.1.1 and 8.8.8.8 are treated the same way.
Does it accept an address with a port number?
No. A value like 192.168.1.1:8080 contains a colon and digits after the address, which breaks the IPv4 shape and can produce a misleading IPv6 classification. Strip the port first.
Free, online, and private
Free to use
IP Address Validator is completely free. There is no account to create, no login, and no hidden charge or usage limit.
Runs online in your browser
It is a free online tool that runs entirely in your browser. Nothing to download or install — open the page and start using it right away.
Your data stays private
All processing happens locally on your device. Your input is never uploaded, stored, or tracked, so it never leaves your browser.
How IP Address Validator behaves in detail
These are the specifics of this implementation — the exact ranges, defaults and fixed settings you are working with.
| Parameter | Value |
|---|---|
| IPv4 rule | four dot-separated groups of one to three digits, each value between 0 and 255 |
| IPv6 rule | any combination of hex digits and colons that contains at least one colon |
| Check order | IPv4 first; the IPv6 test runs only when the IPv4 pattern fails |
| Verdicts | ✓ Valid IPv4, ✓ Valid IPv6, or ✗ Invalid IP address |
| Leading zeros | accepted in IPv4 — 192.168.001.001 is reported as valid |
Compiled from the implementation of this tool and checked against it by itoolnet.
What IP Address Validator does not do
Knowing the edges of a tool saves more time than another list of its features. These are the cases where it will not do what you might expect.
- The IPv6 test is a character-class test, not a structural one. It asks only that every character be a hex digit or a colon and that at least one colon be present, so ":", ":::", "1:2" and "a::b::c" are all reported as valid IPv6 addresses.
- IPv4 groups are checked for value but never for meaning. Leading zeros pass, and nothing is compared against loopback, private or reserved blocks, so the tool tells you the shape of an address and says nothing about whether it can be routed.
- Mixed forms and prefixes are rejected. An IPv4-mapped address such as ::ffff:192.168.1.1 contains dots that the IPv6 character class forbids and is not four dot-separated groups either, so it fails; fe80::1/64 fails in the same way because the slash is not allowed.
Tested and documented by itoolnet, the team that builds and maintains this site.