What an IP address is
Every device that talks on the internet needs an address so that the answers find their way back, just as a letter needs a return address. That is the IP address, and every website you open receives yours with each request, because without it the server could not reply. This page asks our server which address your request came from and shows it to you.
The address shown is the public one, the address your traffic leaves from. At home that is normally your router, which hands out its own private addresses to your phone, laptop and TV and translates between them and its single public address. On a mobile network it is an address of your provider, and if you use a VPN or a proxy, it is the address of that server, because that server is what actually connects to us.
IPv4 and IPv6
There are two versions of the internet protocol in use. RFC 791, from 1981, defines IPv4 with addresses of four octets, 32 bits, written as four numbers from 0 to 255, like 192.0.2.44. That allows at most 2³² = 4,294,967,296 addresses. RFC 8200, the current IPv6 standard, increases the address size from 32 to 128 bits.
IPv6 addresses are written as eight groups of four hexadecimal digits separated by colons. RFC 4291 lets you drop leading zeros in a group and replace one run of all-zero groups with a double colon, so 2001:0db8:0000:0000:0000:0000:0000:0001 becomes 2001:db8::1. The address checker on this page shows the full form of any IPv6 address you enter.
| IPv4 | IPv6 | |
|---|---|---|
| Length | 32 bits | 128 bits |
| Written as | 192.0.2.44 | 2001:db8::1 |
| Possible addresses | about 4.3 billion | about 3.4 × 10³⁸ |
| Private or local | 10/8, 172.16/12, 192.168/16 | fc00::/7, fe80::/10 |
| Loopback | 127.0.0.1 | ::1 |
The example addresses in this guide come from blocks reserved for documentation, so they never belong to a real device. The IANA IPv4 and IPv6 special-purpose registries list every reserved block, and the checker uses them.
Private addresses, NAT and carrier-grade NAT
RFC 1918 sets aside three IPv4 blocks for private networks: 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.31.255.255 and 192.168.0.0 to 192.168.255.255. Routes to them are not passed on between networks, so the same 192.168.1.20 can exist in many separate networks at once. Your router connects them to the internet with address translation. RFC 3022 describes Network Address Port Translation (NAPT), which translates many private addresses and their ports into a single address and its ports. That is why every device in your home shows up with the same public IP here.
Some providers add a second layer. RFC 6598 reserves 100.64.0.0/10 as shared address space for carrier-grade NAT, the addresses between a provider's NAT equipment and its customers' routers. If your router shows an address from 100.64.0.0 to 100.127.255.255 on its internet side, you share your public address with other customers of your provider, and the address shown here differs from the one in your router.
What else your browser tells every site
The IP address is not the only thing a site learns. With every request your browser sends a User-Agent header, which MDN describes as a string that lets servers identify the application, operating system, vendor and version. MDN also notes that supporting browsers now reduce the details in it to limit fingerprinting, which is why some versions show up as fixed values. The user agent parser explains every part of the string.
Your preferred languages travel in the Accept-Language header. According to MDN, browsers set it from the language of their interface plus any languages you added in the settings, and Safari and Chrome's incognito mode list only one language for privacy. Time zone, screen size and window size are not sent by themselves, but any page that runs JavaScript can read them, exactly the way the table on this page does. MDN names fingerprinting as the reason browsers trim these details: combined, they can help tell one browser apart from others.
How this page handles your IP address
Your browser asks our server for your address with one request, and the server answers with the address and its version, nothing else. The script that answers writes no log line and keeps no copy. The only thing it keeps is a short rate limit to stop abuse: a salted one-way hash of the address with the times of its requests in the last minute. Older entries are removed the next time anyone loads the page. Our hosting provider's web server keeps its normal access logs, and those are outside this page's control.
There is no location lookup on this page, because that would mean sending your address to an outside service. Everything else in the table above is read in your browser and goes nowhere. To look up the DNS records of a domain instead, use the DNS lookup.
How to use the IP address tool
- 1Open the page. Your public IP address appears at the top with its version, IPv4 or IPv6.
- 2Press Copy IP to put it on the clipboard, or Check again after you switch networks or turn a VPN on or off.
- 3Look through the table to see the details your browser shares with every site, from the user agent to your time zone.
- 4Type any address into the checker to see whether it is IPv4 or IPv6, public or private, and which range it belongs to.
Frequently asked questions
What is my IP address?
It is the address your device uses on the internet, and the one at the top of this page is the public address our server saw when your browser connected. At home that is usually the address of your router, which all your devices share. On a phone network it belongs to your provider, and with a VPN or proxy it belongs to that server.
Why does the page show IPv4 when I also have IPv6?
The page shows the address your browser used for this one connection. A connection can have both an IPv4 and an IPv6 address, and the browser picks one of them for each site, depending on what the site and your network support. You only see the one that was used to reach our server.
What is the difference between a public and a private IP address?
A public address can be reached on the internet. Private addresses are for home and office networks: RFC 1918 sets aside 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 for that, and they are not routed on the internet. Your router gives your devices private addresses and translates them to its public one, a method RFC 3022 calls NAPT.
What does an IP address starting with 100.64 mean?
Addresses from 100.64.0.0 to 100.127.255.255 are shared address space, set aside in RFC 6598 for carrier-grade NAT. A provider uses them between its own NAT equipment and its customers, so many customers share one public address. If your router shows such an address on its internet side, your provider uses carrier-grade NAT.
Does this page store my IP address?
No. Our server reads it only to send it back to you, and the script writes no log and keeps no copy. To stop abuse, it counts requests per address over one minute, using a salted one-way hash instead of the address itself, and drops entries older than a minute. Our hosting provider's web server keeps its normal access logs, which this page does not control.
How do I check my IP address with a VPN on?
Turn the VPN on and press Check again. The address shown is then the one of the VPN server, because that server connects to our site for you. If it still shows your usual address, the VPN is not carrying your browser traffic. This page looks up no location and sends your address to no other service.