IP Address Checker
API & BackendValidate any IPv4 or IPv6 address and see what it is — public, private, loopback or reserved.
Runs entirely in your browser — nothing is uploaded
Features
- Validates IPv4 and IPv6, and says exactly why an address is wrong.
- Classifies the address: public, private, loopback, link-local, multicast or reserved.
- Shows decimal, hexadecimal, binary and reverse-DNS forms.
- Add a CIDR prefix for the network, broadcast address and usable host count.
- Pure arithmetic in your browser — no lookup, so nothing is sent anywhere.
How to use the IP Address Checker
- 1Paste an IPv4 or IPv6 address, with or without a /prefix.
- 2Read the classification to see whether it is routable on the internet.
- 3Add a prefix such as /24 to get the subnet details.
Frequently asked questions
What is a private IP address?
One from a range reserved for local networks — 10.x.x.x, 172.16-31.x.x and 192.168.x.x — which routers will not forward across the internet. That is why the same 192.168.1.1 exists in millions of homes at once, and why a private address tells you nothing about who is using it.
Why is my IP address rejected as invalid?
Usually one part is above 255, there are not exactly four parts, or a part has a leading zero. Leading zeros are genuinely ambiguous — some software reads 010 as octal 8 — so 192.168.01.01 is rejected rather than guessed at.
Does this tell me who owns an address?
No, and deliberately so. Everything here is worked out from the address itself in your browser, so nothing you paste is transmitted. Ownership needs a WHOIS query and location needs a geolocation database, both of which mean sending the address to someone else.