Where the address is used
A public IP address belongs to address space used for routing on the public internet. A private address is used inside a network, such as a home or office. Separate homes can reuse the same private IPv4 addresses because their local networks are distinct. Public addressing does not automatically make a device reachable: routes, firewalls and whether an application accepts incoming connections still determine what can connect.
Recognizing private IPv4 ranges
The private IPv4 ranges are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. A computer might use 192.168.1.20 to communicate with a home router. This is an example, not a measurement of your connection. Not every address beginning with 172 is private: the reserved range runs from 172.16 through 172.31. Loopback and link-local addresses have separate purposes, so all non-public addresses should not be treated as one category.
How a shared exit works
Network address translation, or NAT, commonly lets several devices use one public IPv4 address. Address and port mappings help replies reach the connection that requested them. Providers may add another translation layer, known as carrier-grade NAT. The shared range 100.64.0.0/10 was reserved for such arrangements and is distinct from the three private ranges above. Whether a subscriber receives a dedicated public address depends on the access service.
What this changes in practice
Ordinary browsing and messaging usually work without manual address configuration. Hosting a service or accessing equipment remotely requires more care: a local forwarding rule alone cannot remove every upstream restriction. IPv6 also has address scopes, including global and local uses. A globally addressed device still needs appropriate access controls. Determine which address and network boundary you are discussing before deciding whether remote access is possible.
Does a router WAN address guarantee a dedicated public IPv4?
WAN describes the upstream interface, not the allocation type. Its address may still be private or shared by an ISP. Even if it matches a lookup result, inbound access depends on firewall rules, mappings and provider policy. For remote access, confirm both allocation and incoming-connection restrictions rather than relying on an address match.