What Is My IP Address?

How It Works

Every device that connects to the internet is assigned an IP address — a numeric label that uniquely identifies it on the network, much like a postal address identifies a building. Understanding what an IP address is, why it matters, and how tools like this one detect it is useful for anyone doing web development, network troubleshooting, or privacy research.

What Is an IP Address?

IP stands for Internet Protocol, and an IP address is the fundamental identifier used to route data packets across the global network. When your browser requests this page, your router sends that request outward carrying your public IP address as the return address. Web servers read that address and send the response back to the right place. Without IP addresses, the internet would have no way to know where to deliver anything.

IPv4 vs IPv6

The original IP address format — IPv4 — uses four groups of decimal numbers separated by dots, such as 203.0.113.42. Each group is an 8-bit number ranging from 0 to 255, giving just over four billion possible addresses in total. As the internet grew, this pool was exhausted. IPv6 was developed as the successor: it uses eight groups of four hexadecimal digits separated by colons, for example 2001:0db8:85a3:0000:0000:8a2e:0370:7334. IPv6 provides 340 undecillion addresses — enough for every grain of sand on Earth to have billions of its own. Most modern devices and networks support both simultaneously, a setup called dual-stack. This tool detects which format your connection uses and labels it accordingly.

Public vs Private IP Addresses

Your home router has two addresses: a private IP (something like 192.168.1.5) that is only meaningful inside your local network, and a public IP that is exposed to the wider internet. Network Address Translation (NAT) sits in your router and maps many private addresses to a single public one. This tool detects and shows your public IP — the one external servers see — because that is the address your browser connects from.

How Proxy Headers Work

When your traffic passes through a proxy, load balancer, or CDN like Cloudflare, the TCP connection that actually reaches the web server originates from the proxy IP address rather than yours. To preserve the original client address, proxies typically add HTTP headers such as X-Forwarded-For, X-Real-IP, or (in the case of Cloudflare) CF-Connecting-IP. This tool checks those headers in priority order: Cloudflare first (most reliable when Cloudflare is present), then X-Real-IP, then the first address in X-Forwarded-For, and finally the raw TCP connection address. Important caveat: these headers can be spoofed by a malicious client, so they should never be trusted as definitive proof of origin in a security context.

VPNs and What This Tool Shows

A Virtual Private Network (VPN) routes your traffic through a server operated by the VPN provider. From the outside internet perspective, your requests appear to originate from the VPN server IP address — not your home address. If you are connected to a VPN when you load this page, the IP shown here belongs to your VPN exit node. This is intentional: the tool shows the IP address that the internet actually sees, which is exactly what you want to verify when testing whether a VPN is working correctly.

User Agent String

Alongside your IP address, this tool displays your browser User-Agent string — a text header that browsers send with every HTTP request, identifying the browser name, version, rendering engine, and operating system. Web servers use it for analytics, feature detection, and sometimes serving different content to different platforms. It is not a unique identifier on its own, but combined with other signals it contributes to browser fingerprinting.

Screen and Viewport Size

Screen resolution is a property of your physical display hardware, while viewport size is the portion of that screen actually available to browser content after the browser chrome (tabs, address bar) is subtracted. Both values are filled in client-side by JavaScript since the server cannot know them. They are commonly used by web developers to debug responsive layout issues.