What Is My IPv4 Address? Find Your IP + Full Guide

What IPv4 actually is

IPv4 (Internet Protocol version 4) is a 32-bit addressing scheme defined in RFC 791 back in September 1981. Every IPv4 address is a 32-bit binary number, which is usually written as four 8-bit chunks called octets. Each octet can hold a value from 0 to 255, giving you the familiar dotted-decimal format like 8.8.8.8 or 192.168.1.1.

When you open a website, your device wraps its request in an IP packet. The packet header carries a source IPv4 (yours) and a destination IPv4 (the server’s). Routers along the path only need to look at the destination to decide where to forward the packet — that simple design is what allowed the Internet to scale into billions of nodes.

The 4.3 billion address ceiling

Because an IPv4 address is 32 bits, the total pool is 2³², which works out to exactly 4,294,967,296 possible addresses — roughly 4.3 billion. In 1981 that felt like an inexhaustible supply. By February 2011 IANA, the global allocator, handed out the last block. The five regional registries (ARIN, RIPE, APNIC, LACNIC, AFRINIC) burned through their remaining inventories between 2011 and 2019. Today, any fresh IPv4 block generally has to be bought on a secondary market for roughly $30–$50 per address.

Exhaustion doesn’t mean IPv4 is broken — it means there aren’t new ones to hand out. The workarounds (NAT, CGNAT, and IPv6) are why you still have Internet access without a guaranteed unique IPv4 of your own.

How dotted decimal maps to binary

Take 192.168.1.1. Each number is one byte. In binary, that’s 11000000.10101000.00000001.00000001. Routers don’t care about the dots or the decimals — those are for humans. The 32 bits are what actually travel over the wire. When you see someone write an IP as a single huge number like 3232235777, they’ve simply concatenated the bits and read them as one integer.

Public vs private IPv4 ranges

Not every IPv4 address is routable on the open Internet. RFC 1918 carves out three private ranges that anyone can use inside their own network without coordination:

• 10.0.0.0/8 — ~16.7 million addresses. Common in corporate networks.
• 172.16.0.0/12 — ~1 million addresses. Used by Docker’s default bridge and many VPNs.
• 192.168.0.0/16 — 65,536 addresses. The default for almost every home router.

There’s also 169.254.0.0/16, called APIPA (Automatic Private IP Addressing). If your device can’t reach a DHCP server, it self-assigns an address from this block so at least local communication can happen. Seeing a 169.254 address is almost always a sign that DHCP has failed.

CIDR in 30 seconds

CIDR (Classless Inter-Domain Routing) notation adds a slash and a number after an IP, like 192.168.1.0/24. The number tells you how many leading bits define the network. /24 means the first 24 bits are the network, the last 8 are hosts, so you get 256 addresses (254 usable, minus network and broadcast). /16 gives 65,536. /8 gives 16.7 million. The smaller the number, the bigger the block.

How to find your IPv4 address

There are two IPv4 addresses that matter to you: the private one your router assigned to your device, and the public one your ISP hands to your whole home network. Web-based checkers (including ours) always show your public IP, because that’s what the server sees. To get your private IP, you need to ask the device directly.

Windows

Open Command Prompt or PowerShell and run ipconfig. Look for the adapter you’re actually using (usually “Wireless LAN adapter Wi-Fi” or “Ethernet adapter”). The IPv4 Address line is your private IP. If you want your public IP from the command line, curl ifconfig.me works in Windows 10/11.

macOS

Open System Settings → Network, pick your active connection, and the IPv4 address shows in the details panel. From Terminal, run ifconfig | grep "inet " or the modern equivalent ipconfig getifaddr en0 (use en1 for Wi-Fi on some models).

Linux

Use ip addr show or the shorter ip -4 a to see all IPv4 addresses assigned to your interfaces. hostname -I prints just the addresses, space-separated — handy for scripts.

iOS and Android

On iOS, go to Settings → Wi-Fi, tap the blue info icon next to your network. On Android, Settings → Network & Internet → Wi-Fi, tap the network, and expand the advanced/details section. You’ll see the private IPv4 your router assigned you.

Using a web tool

For your public IP, the fastest path is a browser-based checker. Ours pulls the address the server sees, along with the ISP and approximate geolocation, with no install and no login.

Why IPv4 is still everywhere

Despite being “exhausted,” IPv4 still carries the majority of Internet traffic. Two technologies keep it viable:

• NAT (Network Address Translation) lets hundreds of devices behind your router share one public IPv4. Your router rewrites outbound packet headers, keeping a table of which internal device expects which reply.
• CGNAT (Carrier-Grade NAT) pushes this one level up. Your ISP puts thousands of customers behind a single public IPv4, typically using the 100.64.0.0/10 shared address space defined in RFC 6598.

IPv6 is the long-term answer, but IPv4 won’t disappear any time soon — too many services, routers, and devices still default to it. Most of the Internet runs dual-stack, speaking both protocols at once.

Special-purpose IPv4 addresses worth knowing

Out of the 4.3 billion IPv4 addresses, several large blocks are reserved for specific purposes and never appear on the open Internet. Recognizing these saves you time when troubleshooting.

127.0.0.0/8 — loopback

Every IPv4 stack treats 127.0.0.1 as “this machine”. Traffic sent here never touches a physical network card; it loops back inside the OS. Testing a local web server? You visit 127.0.0.1:8080 or localhost, which resolves to the same place. The entire 127.0.0.0/8 range is reserved, though only 127.0.0.1 is used in practice.

0.0.0.0 — the “unspecified” address

Means different things in different contexts. On a client, it signals “no address yet”—you’ll see it briefly when a device is negotiating DHCP. On a server, binding a listening socket to 0.0.0.0 means “accept connections on every interface I have”. Never route-able.

255.255.255.255 — local broadcast

Sent here, a packet goes to every device on the local subnet at once. Used by DHCP discovery (the client doesn’t yet know who the server is) and by old-school network protocols like WINS. Routers drop broadcasts, so they never cross subnet boundaries.

169.254.0.0/16 — APIPA / link-local

If a device is configured for DHCP but no DHCP server answers, it will self-assign an address from this range as a fallback. Seeing a 169.254.x.x address on your machine almost always means “your router isn’t responding to DHCP” — time to reboot the router or check the cable.