Private IP Address Ranges Explained (10.x, 172.16.x, 192.168.x)

Every private network, whether it's a home Wi-Fi router or a large office LAN, pulls its device addresses from one of three reserved blocks. These ranges were set aside by IANA (the organization that manages global IP address allocation) specifically so they'd never be used on the public internet, which is why the same private ip address, like 192.168.1.1, shows up on millions of different home networks around the world without ever conflicting with anyone else's network.

The three private IP ranges

10.0.0.0 to 10.255.255.255

The largest of the three, over 16 million addresses. Common on larger home routers, corporate networks, and cloud or VPN setups where a lot of address space is needed, since a single 10.x network can comfortably support tens of thousands of devices without running out of room.

172.16.0.0 to 172.31.255.255

A mid-sized range, roughly 1 million addresses. You'll see this on some business routers and it's Docker's default networking range for containers, which is one reason developers run into it more often than typical home users.

192.168.0.0 to 192.168.255.255

The default range for the vast majority of home routers. Usually shows up as 192.168.0.x or 192.168.1.x, and it's small enough (about 65,000 addresses) to comfortably cover a household or small office without any special configuration.

IP classes: private and public, where these ranges come from

These three ranges map onto what used to be called IP address classes, a system from the early internet that grouped addresses by their leading bits, before CIDR notation became the standard way of describing network sizes:

• Class A (1.0.0.0 to 126.255.255.255), the private slice of this class is the 10.0.0.0/8 range
• Class B (128.0.0.0 to 191.255.255.255), the private slice is 172.16.0.0/12
• Class C (192.0.0.0 to 223.255.255.255), the private slice is 192.168.0.0/16

Modern networking mostly ignores strict class boundaries in favor of CIDR notation (the /8, /12, /16 you see above), but the class system is still why these three specific ranges were chosen, one carved out of each class, so private addressing was possible at any network size, from a small apartment to a large enterprise. Not sure where your own address falls? See whether your IP falls in a private range instead of working through the class math by hand.

Is 30.0.0.0/8 public or private?

Public. The 30.0.0.0/8 block sits inside the Class A public range and isn't one of the three reserved private blocks listed above. Historically, 30.0.0.0/8 was allocated to the US Department of Defense, and while its exact usage has shifted over the years, it has never been designated as private address space. If a network device shows an address starting with 30, it's using, or expecting to reach, public address space, not a private LAN range. The same logic applies to any address people ask about: check it against the three ranges above, and if it doesn't fall inside them, it's public, with the loopback (127.x) and CGNAT (100.64.x to 100.127.x) exceptions covered in our public vs private IP guide.

Why private ranges can repeat across millions of networks

This is the part that surprises people the first time they think it through: your home router might be using 192.168.1.1, and so might your neighbor's, your office's, and a coffee shop's down the street, all at the same time, without any conflict. That's only possible because private IP addresses are never routed across the public internet. Your router silently rewrites your device's private IP into its own public IP whenever traffic leaves your network, a process called NAT (Network Address Translation), so the outside world never actually sees the private address at all.

Common private IP range questions

• Can I use any private range I want on my own network? Yes, all three are equally valid for private use. Most home routers default to 192.168.x simply because it's a smaller, easier-to-manage block for typical household device counts.
• Why does my office use 10.x instead of 192.168.x? Larger organizations often pick 10.x specifically because of its size, it comfortably handles thousands of devices across multiple departments or buildings without needing to subdivide further.
• Is 172.22.16.71 public or private? Private, it falls inside the 172.16.0.0 to 172.31.255.255 block.

Quick lookup table

Use a private IP range checker

Doing the range math manually works, but it's easy to mess up with longer addresses or ones near a range boundary. Confirm it with our private IP range checker and get an instant answer along with the specific range it belongs to, no need to count octets by hand.