Every device connecting to the internet needs a public IP address, and it's easy to assume that number is some kind of precise digital location pin. It isn't. It's closer to a mailing address for your internet service provider's network -- useful, but far less exact than people expect.
It's assigned by your ISP, not your device
Your public IP isn't baked into your laptop or phone. It's handed to you by whichever network you're connected to -- your home ISP, your mobile carrier, a coffee shop's Wi-Fi. Switch networks and the IP changes with it. This is also why the IP a website sees is the ISP's exit point to the internet, not your device itself.
Why it changes (and sometimes doesn't)
Most home and mobile connections use dynamic IPs: your ISP maintains a pool of addresses and assigns you one that can change on reconnect or after a set lease period. Some connections -- often business lines, or ones you've specifically paid for -- get a static IP that stays fixed. If your IP looks identical every time you check, you likely have a static IP or you're routing through a VPN.
Location accuracy stops at the city, usually
IP geolocation databases map ranges of addresses to a region based on where the ISP registered them, not GPS. That's normally good enough to get your city or metro area right, but it can be off entirely if your ISP routes traffic through a hub in a different city, or if you're on a mobile network that shares infrastructure across a wide area. It will never resolve to your exact street address -- that level of precision simply isn't in the data.
VPNs and proxies move the pin, not you
When you connect through a VPN, the IP a website sees belongs to the VPN server, not your actual connection. That's the entire point of using one -- but it also means any "location" a site shows you is the VPN exit node's location, which can be a different country from where you're actually sitting.
IPv4 vs IPv6
You might notice two different-looking addresses: a shorter IPv4 address (like 203.0.113.4) and a much longer IPv6 address (like 2001:db8::1). IPv4 has a limited pool of addresses that's been exhausted for years, which is part of why ISPs share and rotate them so aggressively. IPv6 has a vastly larger address space, and more networks are rolling it out alongside or instead of IPv4 -- so seeing both isn't unusual.
Checking your own
If you want to see exactly what's publicly visible from your current connection -- your IP and the rough location tied to it -- the My IP Address tool shows it instantly, without logging or storing anything.