What is an IP address?
Every device that talks to other devices over the internet (a phone, a laptop, a printer, a smart TV) needs an address so the data knows where to go. That address is the IP address, short for Internet Protocol address.
Think of it as the postal address of your home: if someone wants to send you a letter, they need your exact address so it doesn't end up at your neighbour's.
Public IP and private IP
Your public IP is the one your internet provider gives your connection, and it's the one the rest of the internet sees. It's the address shown at the top of this page. Every device at home goes out to the internet through your router using that same public IP.
Inside your home, the router gives each device a private IP, usually something like 192.168.1.20 or 10.0.0.5. These addresses only make sense inside your own network: millions of homes use exactly the same private IPs without any conflict, because they never leave the router.
Going back to the postal example: the public IP is the address of the building, and the private IP is the flat number inside it.
Dynamic or static IP
Most home connections have a dynamic IP: the provider can change it from time to time, for example when the router restarts. If you need it to always be the same (to reach a camera or a server at home from outside, for instance), you can ask your provider for a static IP, sometimes for an extra fee.
IPv4 and IPv6
An IPv4 address is made of four numbers from 0 to 255, such as 203.0.113.45. That gives just over 4 billion addresses, which have long since run out. IPv6 was created to fix that: its addresses are much longer, such as 2001:db8::8a2e:370:7334, and there are enough of them for every device on the planet many times over. The label under your IP tells you which one your connection is using right now.
What is CG-NAT?
Because IPv4 addresses are scarce, many providers, especially mobile and some fibre operators, use CG-NAT (Carrier-Grade NAT): several customers share the same public IP. For browsing, streaming or video calls you won't notice any difference, but it can get in the way of opening ports, running a server or a camera at home, or some online games. If that's your case, ask your provider whether they can give you your own public IP.
Can two devices have the same IP?
Not on the internet: a public IP belongs to one connection at a time (or to a group of customers sharing it through CG-NAT). Private IPs, on the other hand, are repeated in millions of homes, and that's fine, because each one only exists inside its own network.