The Quick Answer
An IP address is a unique numerical identifier assigned to every device connected to a network, enabling data to be routed between a source and destination across the internet.
Every time you load a website, send an email, or stream a video, IP addresses tell the network where to send the data and where the response should go back to. Without them, the internet could not function.
There are two versions in use today: IPv4 (e.g., 192.168.1.1) and IPv6 (e.g., 2001:0db8:85a3::8a2e:0370:7334). Most of the internet still runs on IPv4, but IPv6 adoption is growing because we have run out of IPv4 addresses.
Use our IP Address Converter to convert between formats, or the IP to Binary tool to see the underlying binary representation.
What Is an IP Address?
IP stands for Internet Protocol. An IP address is a numerical label that serves two functions:
- Host identification -- it uniquely identifies a device on a network
- Location addressing -- it provides routing information so data packets can travel from point A to point B
Think of it like a postal address for your device. When your browser requests a web page, the request packet carries your IP address as the return address so the server knows where to send the response.
IP addresses are defined in RFC 791 (IPv4) and RFC 8200 (IPv6).
IPv4: The Original Standard
IPv4 addresses are 32 bits long, written as four decimal numbers separated by dots. Each number (called an octet) represents 8 bits and ranges from 0 to 255.
Format: 0.0.0.0 to 255.255.255.255
Example: 192.168.1.1
In binary, that address looks like: 11000000.10101000.00000001.00000001
Total Address Space
2^32 = 4,294,967,296 addresses (approximately 4.3 billion).
That sounds like a lot, but it is not. Large blocks are reserved for special purposes (private networks, multicast, loopback), and the remaining public addresses must serve every internet-connected device on earth. The pool was officially exhausted when IANA allocated the last IPv4 blocks to regional registries on February 3, 2011.
IPv6: The Solution to Exhaustion
IPv6 addresses are 128 bits long, written as eight groups of four hexadecimal digits separated by colons.
Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Leading zeros within a group can be omitted, and consecutive groups of all zeros can be replaced with :: (once per address):
2001:db8:85a3::8a2e:370:7334
Total Address Space
2^128 = 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses -- approximately 340 undecillion. That is roughly 4.8 x 10^28 addresses for every person on earth.
IPv6 was designed not just for quantity but also for simplicity. It eliminates the need for NAT in most cases, simplifies routing headers, and has built-in support for IPsec encryption. The standard is defined in RFC 8200.
Adoption Status
As of early 2026, roughly 45% of traffic to Google uses IPv6. Adoption varies widely by country -- India, the United States, and Germany lead with over 50% IPv6 usage, while many regions remain below 20%. The transition is gradual because IPv4 and IPv6 are not directly compatible; networks run both in parallel (called dual-stack).
Public vs Private IP Addresses
Private Addresses
Three ranges are reserved for use inside local networks, as defined in RFC 1918:
| Range | CIDR Notation | Total Addresses | Typical Use |
|---|---|---|---|
| 10.0.0.0 -- 10.255.255.255 | 10.0.0.0/8 | 16,777,216 | Large enterprise networks |
| 172.16.0.0 -- 172.31.255.255 | 172.16.0.0/12 | 1,048,576 | Medium-sized organizations |
| 192.168.0.0 -- 192.168.255.255 | 192.168.0.0/16 | 65,536 | Home and small office networks |
These addresses are not routable on the internet. Any organization can use them internally without coordination with anyone else. Your home router almost certainly assigns devices addresses in the 192.168.x.x range.
Public Addresses
Public IP addresses are globally unique and routable on the internet. When you visit a website, that site sees your public IP address. Your ISP assigns your public IP from a pool allocated to them by a regional internet registry.
NAT: Bridging the Gap
Network Address Translation (NAT) is the technology that allows multiple devices with private IP addresses to share a single public IP address. Your home router performs NAT: it maintains a translation table tracking which internal device made which request, so return traffic gets delivered to the correct device.
Without NAT, every device would need its own public IPv4 address, and we would have run out of addresses far sooner. NAT has been the primary stopgap measure that kept IPv4 functional decades beyond its original capacity.
How IP Addresses Are Assigned
The allocation of public IP addresses follows a hierarchical system:
- IANA (Internet Assigned Numbers Authority) -- manages the global pool
- RIRs (Regional Internet Registries) -- receive large blocks from IANA and distribute them within their regions:
- ARIN -- North America
- RIPE NCC -- Europe, Middle East, Central Asia
- APNIC -- Asia Pacific
- LACNIC -- Latin America and Caribbean
- AFRINIC -- Africa
- ISPs -- receive blocks from their regional RIR and assign addresses to customers
- End users -- receive one or more public IPs from their ISP
Inside Your Home Network: DHCP
Your home router uses DHCP (Dynamic Host Configuration Protocol) to automatically assign private IP addresses to every device that connects. When your phone joins your WiFi, DHCP gives it an address like 192.168.1.47, a subnet mask, a default gateway (the router itself), and DNS server addresses -- all without any manual configuration.
DHCP leases are temporary. The address is yours for a set period (often 24 hours); when the lease expires, your device requests a renewal and may get the same address or a different one.
Static vs Dynamic IP Addresses
Dynamic IPs
Most residential internet connections use dynamic IP addresses. Your ISP assigns your router a public IP that may change periodically -- when the DHCP lease expires, when you restart the router, or when the ISP rotates assignments.
Dynamic IPs are cheaper for ISPs to manage because they can reuse addresses across customers who are not online simultaneously.
Static IPs
A static IP address never changes. Businesses use them for:
- Hosting web servers, email servers, or VPNs
- Remote access to office networks
- Running services that require a consistent address (DNS, security cameras)
Static IPs typically cost more from an ISP because the address is permanently reserved for one customer.
What Your IP Address Reveals (and What It Does Not)
What it reveals
- Approximate geographic location -- typically accurate to the city or metro area, sometimes only to the state or region
- ISP name -- the company providing your internet connection
- Connection type -- residential, business, mobile, or data center
- ASN (Autonomous System Number) -- the network operator
What it does NOT reveal
- Your name or personal identity
- Your exact street address
- Your browsing history
- What is on your device
- Your phone number or email
IP geolocation databases (used by websites) typically achieve city-level accuracy about 50-80% of the time. They work by mapping known IP ranges to geographic locations, but this data is imperfect and often outdated. VPN and mobile users frequently show locations far from where they actually are.
Law enforcement can obtain your identity from your ISP via a court order or subpoena, but an ordinary person seeing your IP address cannot identify you.
Special IP Addresses
Localhost
127.0.0.1 (IPv4) and ::1 (IPv6) are the loopback addresses, commonly called localhost. Traffic sent to this address never leaves the machine -- it loops back to the sender. Developers use localhost extensively for testing web servers, databases, and APIs running on their own computer.
The entire 127.0.0.0/8 block (127.0.0.0 -- 127.255.255.255) is reserved for loopback, though 127.0.0.1 is the one universally used.
Other Reserved Addresses
| Address | Purpose |
|---|---|
| 0.0.0.0 | "This network" -- used as a default or unspecified address |
| 255.255.255.255 | Broadcast -- sends to all devices on the local network |
| 169.254.0.0/16 | Link-local -- auto-assigned when DHCP fails |
| 224.0.0.0/4 | Multicast -- one-to-many communication |
Try It
Convert IP addresses between decimal, binary, and hexadecimal formats with our IP Address Converter, visualize the binary structure with IP to Binary, or calculate network ranges with the CIDR Calculator.
For deeper coverage of network partitioning, see our guides on subnetting and CIDR notation.
FAQ
Can someone find my exact location from my IP address?
No. An IP address reveals your approximate geographic location, typically accurate to the city or regional level. It does not reveal your street address, name, or any personal identity. Law enforcement can request precise records from your ISP with a court order, but a random person on the internet cannot pinpoint your location from your IP alone.
What is the difference between IPv4 and IPv6?
IPv4 uses 32-bit addresses written as four decimal numbers (e.g., 192.168.1.1), providing about 4.3 billion unique addresses. IPv6 uses 128-bit addresses written as eight groups of hexadecimal digits (e.g., 2001:0db8::8a2e:0370:7334), providing 340 undecillion addresses. IPv6 was created because the world ran out of IPv4 addresses.
How do I find my IP address?
To find your public IP, visit a site like whatismyipaddress.com or search "what is my IP" in Google. To find your private (local) IP, on Windows run ipconfig in Command Prompt, on macOS/Linux run ifconfig or ip addr in the terminal, or check your WiFi connection details on a phone.
Why are we running out of IP addresses?
IPv4 provides approximately 4.3 billion addresses. With billions of internet-connected devices worldwide -- smartphones, laptops, IoT sensors, servers -- the supply was exhausted. IANA allocated the last top-level IPv4 blocks to regional registries in February 2011. NAT and IPv6 are the primary solutions to this exhaustion.
What is NAT and why does it matter?
NAT (Network Address Translation) allows multiple devices on a private network to share a single public IP address. Your home router uses NAT so that every phone, laptop, and smart device in your house can access the internet through one public IP assigned by your ISP. NAT has been critical in extending the useful life of IPv4.
Is my IP address permanent?
Most residential internet connections use dynamic IP addresses that change periodically -- when your router restarts, when your ISP's DHCP lease expires, or at regular intervals. Businesses often pay for static IP addresses that do not change, which is necessary for hosting servers or remote access.
What is the difference between a public and private IP address?
A public IP address is globally unique and routable on the internet -- it is what websites see when you visit them. A private IP address (e.g., 192.168.1.x) is used only within a local network and is not directly reachable from the internet. Your router translates between the two using NAT.
What does 127.0.0.1 mean?
127.0.0.1 is the IPv4 loopback address, also called localhost. It always refers to the device you are currently using. Traffic sent to 127.0.0.1 never leaves your machine -- it loops right back. Developers use it to test network services locally. The IPv6 equivalent is ::1.
Can two devices have the same IP address?
Two devices cannot share the same IP address on the same network -- this causes an IP conflict and connectivity problems for both. However, devices on different private networks can use identical private IPs (e.g., both using 192.168.1.5) because those addresses are only meaningful within their own local network.
Does a VPN change my IP address?
Yes. A VPN routes your traffic through a server in another location, so websites see the VPN server's IP address instead of yours. Your actual IP address assigned by your ISP does not change, but it is hidden from the sites and services you connect to through the VPN tunnel.