Public vs Private IP
Devices connected to a home or office network often use more than one type of IP address. Your computer, phone, smart TV, and other devices may each have a private IP address, while the network itself communicates with the internet using a public IP address.
Understanding the difference between public and private IP addresses makes it much easier to understand how home networks, routers, internet connections, and IP lookup tools work.
What is a public IP address?
A public IP address is an IP address used for communication across the internet. It represents an internet-facing network connection and can be routed between networks on the public internet.
For a typical home internet connection, the public IP address is usually assigned by the internet service provider.
When you visit a website, the site normally sees the public IP address through which your traffic reached the internet.
Example of a public IPv4 address
A public IPv4 address may look like:
8.8.8.8
Public addresses must be managed carefully because they are used to identify destinations across interconnected networks.
What is a private IP address?
A private IP address is used inside a local network rather than directly across the public internet.
Your router commonly assigns private IP addresses to devices connected to your home or office network.
For example, a laptop might use:
192.168.1.20
while a phone on the same Wi-Fi network might use:
192.168.1.21
These addresses help devices communicate locally without requiring a separate public IPv4 address for every device.
Private IPv4 address ranges
IPv4 reserves several address ranges for use inside private networks.
| Private range | CIDR |
|---|---|
| 10.0.0.0 – 10.255.255.255 | 10.0.0.0/8 |
| 172.16.0.0 – 172.31.255.255 | 172.16.0.0/12 |
| 192.168.0.0 – 192.168.255.255 | 192.168.0.0/16 |
Addresses inside these ranges are intended for private networks and are not normally routed directly across the public internet.
Public IP vs private IP
| Feature | Public IP | Private IP |
|---|---|---|
| Used on the internet | Yes | No, primarily local networks |
| Usually assigned by | Internet provider | Local router or administrator |
| Visible to websites | Usually yes | Usually no |
| Can be reused on other local networks | No | Yes |
How can many devices share one public IP?
One of the technologies that makes this possible is Network Address Translation (NAT).
In a common home network, devices communicate with the router using their private IP addresses. The router then sends internet traffic through the public IP address assigned to the connection.
This allows many devices to share a single public IPv4 address.
A simplified example might look like this:
- Laptop: 192.168.1.10
- Phone: 192.168.1.11
- Smart TV: 192.168.1.12
- Router's public IP: one address used toward the internet
The router keeps track of network connections so returning traffic can be delivered to the correct device.
Which IP address can websites see?
Websites normally see the public IP address from which your connection reaches them.
They generally do not receive the ordinary private IPv4 address assigned to your device by your home router simply as part of normal internet routing.
This is why an online IP lookup tool may show one address while the network settings on your phone or computer show another.
Why does my device show a different IP address?
Suppose your computer reports:
192.168.1.25
while an online IP lookup service displays a completely different address. Both can be correct.
The first may be the private IP address used inside your local network. The second may be the public IP address used by your internet connection.
Can two homes use the same private IP address?
Yes.
Millions of separate private networks can reuse the same private IP addresses. For example, many routers around the world may assign 192.168.1.2 to a device.
This does not normally create a conflict because each private address exists within its own local network.
Can two devices on the same network use the same private IP?
They normally should not.
Two devices using the same IPv4 address on the same local network can create an IP address conflict, which may prevent one or both devices from communicating correctly.
Routers commonly use DHCP to automatically distribute addresses and reduce the chance of such conflicts.
Is a public IP address always unique?
Public addressing is designed so that routes on the internet can reach the correct destination. However, the way users experience public addressing can be more complicated than a simple one-customer-to-one-address relationship.
Some internet providers use technologies such as Carrier-Grade NAT (CGNAT), allowing multiple customers to share public IPv4 resources.
This is especially useful because the supply of IPv4 addresses is limited.
What is Carrier-Grade NAT?
Carrier-Grade NAT is similar in concept to the NAT commonly performed by a home router, but it operates within the internet provider's network.
As a result, a customer may have a local address assigned by the provider while sharing an internet-facing public IPv4 address with other customers.
CGNAT can affect services that require unsolicited inbound connections, including some forms of remote access, self-hosting, gaming, and port forwarding.
Are private IP addresses more secure?
A private IP address is not directly routable across the public internet in the same way as a public address, but that does not automatically make a device secure.
Network security still depends on factors such as:
- router and firewall configuration,
- software updates,
- strong authentication,
- device configuration,
- and avoiding unsafe services or applications.
Private addressing is a networking mechanism, not a replacement for security controls.
What about IPv6?
IPv6 works differently from the IPv4 environment many users are familiar with. Its enormous address space reduces the need to conserve addresses in the same way IPv4 does.
IPv6 also defines address types intended for different scopes. For example, link-local IPv6 addresses are used for communication on the local network segment, while globally routable IPv6 addresses can be used across the internet.
IPv6 Unique Local Addresses also exist for local networking purposes.
How do I find my private IP address?
Your private or local IP address can usually be found in the network settings of your operating system.
The exact procedure depends on whether you are using Windows, macOS, Linux, Android, iOS, or another platform.
It is often listed as an IPv4 address, local address, Wi-Fi address information, or network interface address.
How do I find my public IP address?
Your public IP address can be checked using an online IP lookup service such as IPScope.
The address displayed may change if you switch internet providers, move from Wi-Fi to mobile data, reconnect through a different network, or use a VPN.
Public and private IP example
Imagine three devices connected to the same home router:
- Computer — 192.168.1.5
- Phone — 192.168.1.8
- Tablet — 192.168.1.12
Each device has a different private address inside the home network. When they connect to a website, however, their traffic may leave through the same public internet connection.
The website therefore sees the public-facing address rather than those three private IPv4 addresses.
Key takeaway
A public IP address is used for communication across the internet, while a private IP address is used inside a local network.
Routers and technologies such as NAT allow many privately addressed devices to communicate through a shared public internet connection.
Related guide
New to IP addressing? Start with What Is an IP Address? for an introduction to Internet Protocol addressing, IPv4, IPv6, routing, and basic IP concepts.
