Quick answer: Your public IP can change when your ISP reassigns a dynamic address, your connection reconnects, you switch networks, or a VPN/proxy changes the network path seen by websites.
Dynamic addresses are normal
Many consumer connections do not keep one public IPv4 address forever. The provider manages a pool of addresses and may assign a different one after a lease or reconnection.
Wi-Fi, mobile and VPN changes
Moving from home Wi-Fi to cellular data usually means using a different provider network and therefore a different public address. A VPN also makes sites see the VPN server’s address instead of the direct connection.
How to confirm a change
Check your address before and after reconnecting with IP Lookup. For a deeper explanation of shared addressing, read our CGNAT guide.
Want to see this in practice? Check your own connection's IP, location and ISP.
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