There are 4,294,967,296 IPv4 addresses, because an IPv4 address is 32 bits long. About 3.7 billion of them can be used on the public internet; the rest are reserved for private networks, multicast and other special uses. The five internet registries ran out of free addresses between 2011 and 2020.
We counted the registries' own files of November 2026. They had handed out 3,687,663,456 addresses, and organizations in the United States hold 1,606,591,392 of them, 43.6%. Set against APNIC Labs' estimate of 4.53 billion internet users, that comes to about 1.2 users per address worldwide. In Iraq it is 101 users per address, and in the United States 0.16.
Why are there 4,294,967,296 IPv4 addresses?
The number comes from the length of the address. RFC 791, the 1981 standard that defines IPv4, says: "Addresses are fixed length of four octets (32 bits)." Thirty-two bits give 2 to the power of 32 combinations, which is 4,294,967,296. People write each address as four numbers from 0 to 255, such as 203.0.113.7.
The space is handed out in blocks. IANA, the body at the top, gave addresses to the registries in blocks that "equate to 1/256th of the entire IPv4 address space", as the Number Resource Organization puts it. Engineers call such a block a /8. One /8 holds 16,777,216 addresses.
How many IPv4 addresses can the public internet use?
About 3.7 billion. IANA keeps a registry of ranges with special jobs: private networks, loopback, testing, multicast and a large block held for "future use" since 1981. We merged every range in IANA's special-purpose registry with the multicast block and counted each address once. They come to 592,709,632 addresses, which leaves 3,702,257,664 for ordinary public use.
| Use | Block | Addresses |
|---|---|---|
| Multicast | 224/4 | 268,435,456 |
| Future use | 240/4 | 268,435,456 |
| Loopback | 127/8 | 16,777,216 |
| "This network" | 0/8 | 16,777,216 |
| Private | 10/8 | 16,777,216 |
| CGNAT | 100.64/10 | 4,194,304 |
| Private | 172.16/12 | 1,048,576 |
| Private | 192.168/16 | 65,536 |
The private ranges are the ones your home router uses, so millions of homes can reuse 192.168.1.1 without a clash. The 100.64/10 block exists for internet providers that share one public address among many customers; our guide to what CGNAT is explains it.
When did IPv4 run out?
IANA's free pool ran out first, on February 3, 2011. The NRO announced that day that "the free pool of available IPv4 addresses is now fully depleted". The five regional registries then spent their last blocks over the next nine years.
Feb 3, 2011
IANA's free pool is depleted
the last /8 blocks go to the five registries
Apr 15, 2011
APNIC reaches its final /8
Asia Pacific
2012
The RIPE NCC reaches its last /8
Europe, Middle East
Sep 24, 2015
ARIN's free pool reaches zero
North America
Nov 25, 2019
The RIPE NCC runs out
a waiting list follows
Jan 13, 2020
AFRINIC enters Phase 2
a small final pool
Aug 2020
LACNIC reserves its last block
Latin America, Caribbean
Running out did not switch anything off. Addresses already handed out keep working, and the registries now live on returned space. On September 24, 2015, ARIN wrote that requests "may be fulfilled via the Wait List for Unmet IPv4 Requests, or through the IPv4 Transfer Market". At the RIPE NCC, an organization that never had IPv4 from it may join a waiting list for "a single /24 allocation", 256 addresses.
How many IPv4 addresses are still free?
Very few. The five registries publish a file of every block they manage, updated daily. In the files of November 5 to 7, 2026, we counted 3,488,064 IPv4 addresses marked available. That is less than a tenth of one percent of the total.
APNIC held 2,908,480 of them and AFRINIC 575,232. The RIPE NCC had 4,096 left, LACNIC 256 and ARIN none. The same files mark another 11,106,400 addresses as reserved, held back by the registries under their own policies.
Who holds the most IPv4 addresses?
By registry, ARIN's region does. ARIN, which serves the United States, Canada and parts of the Caribbean, had handed out 1,644,513,024 addresses. APNIC followed with 888,932,544 and the RIPE NCC with 856,117,152. LACNIC had 181,941,760 and AFRINIC 116,158,976, for 3,687,663,456 in all.
By country, the United States holds more than the next nine countries together:
The lead goes back to the years before the registries existed. In the 1990s, whole /8 blocks of 16,777,216 addresses went to single organizations. IANA's own registry lists 17/8 for Apple Computer in 1992, 19/8 for the Ford Motor Company in 1995 and several blocks for the Defense Information Systems Agency. Many of those early holders were American companies and agencies.
A registry records where the holder is registered, and the addresses can be used anywhere. A cloud company registered in the United States runs servers on every continent, so part of that American space can answer for the rest of the world.
How many internet users share each IPv4 address?
On average about 1.2. APNIC Labs, the research group of the Asia-Pacific registry, estimates how many people use each network from its ad measurements, and its figures add up to 4.53 billion users. The registries have handed out 3.69 billion addresses. Country by country, the gap is far wider than the average:
India shows the scale. APNIC estimates 656 million users there, on 42 million addresses registered in the country, so about 16 users share each one. China has 830 million users on 343 million addresses. Nigeria has 77 million users on 3.2 million addresses. Countries that connected most of their users after the registries ran low hold small blocks, and their providers share addresses among many customers, often through carrier-grade NAT.
The same pattern shows inside single networks. In our CGNAT guide we did this calculation for 42 large networks: Globacom in Nigeria counted 386 users per address, and Comcast in the United States 0.7.
Does IPv6 solve the shortage?
IPv6 removes the limit. RFC 8200 states that "IPv6 increases the IP address size from 32 bits to 128 bits". That gives 2 to the power of 128 addresses, enough to give every device its own.
Adoption is uneven, so IPv4 still carries much of the traffic. APNIC Labs measured 62% of users in the United States as able to use IPv6 in October 2026, against 5.6% in Nigeria. Our guide to CGNAT charts eleven countries. Until a site and its visitors both speak IPv6, every connection still needs an IPv4 address at each end.
What does the shortage mean for proxies?
Addresses have a price. Because new IPv4 space comes only from returns and the transfer market, an address is something people buy and sell. That is why datacenter and ISP proxies are priced per address: our dedicated IPv4 costs $1.58 per IP, and IPv6, which has no shortage, $0.10 per IP. Our comparison of IPv4 and IPv6 proxies says where each one works.
Shared addresses are hard to block. Where hundreds of people share one address, a site that blocks it locks them all out. That is why mobile proxies, which exit from carrier addresses, are costly for a site to refuse.
Home addresses come from the same pool. A residential proxy borrows an address a provider gave to a household, out of the same scarce space. Our guide to residential IP addresses explains how sites read them.
Method
We read the delegated-extended statistics files of the five registries: ARIN and APNIC dated November 7, 2026, the RIPE NCC and LACNIC November 6, and AFRINIC November 5. Each line of such a file is one block, with its country code, size and status. We added up every IPv4 block marked allocated or assigned, by country, and every block marked available or reserved, by registry.
For users we took APNIC Labs' table of estimated users for all 46,219 networks it measures, dated November 2, 2026, and added them up by country. Users per address is one total divided by the other. For the special-purpose space we merged every range of IANA's special-purpose registry with the multicast block 224.0.0.0/4, so no address counts twice.
What this page could not check
- Where addresses are used. The registries record the holder's country. A cloud provider's American space serves the world, and a provider can use addresses leased or transferred from another country.
- Handed out is not in use. Some delegated space sits idle, and no public source counts how much.
- User estimates. APNIC's figures come from ad measurements and add up to 4.53 billion, fewer than some other counts of internet users. Small countries can show extreme ratios.
- Daily change. Transfers move addresses between holders and countries every day. These are the files of November 5 to 7, 2026.
- Check by February 8, 2027.
Sources
- RFC 791: Internet Protocol. IETF, September 1981.
- RFC 8200: Internet Protocol, Version 6 (IPv6) Specification. IETF, July 2017.
- IPv4 Address Space Registry. IANA, last updated October 10, 2025, read November 7, 2026.
- IPv4 Special-Purpose Address Registry. IANA, read November 7, 2026.
- Free Pool of IPv4 Address Space Depleted. Number Resource Organization, February 3, 2011.
- APNIC IPv4 Address Pool Reaches Final /8. APNIC, April 15, 2011.
- ARIN IPv4 Free Pool Reaches Zero. ARIN, September 24, 2015.
- The RIPE NCC has run out of IPv4 Addresses. RIPE NCC, November 25, 2019.
- IPv4 Exhaustion: LACNIC Has Assigned the Last Remaining Address Block. LACNIC, August 28, 2020.
- IPv4 Exhaustion. AFRINIC, read November 7, 2026.
- Delegated-extended statistics files. ARIN, RIPE NCC, APNIC, LACNIC and AFRINIC, November 5 to 7, 2026.
- Visible ASNs: customer populations (estimated). APNIC Labs, November 2, 2026.
- IPv6 measurement per country. APNIC Labs, read October 22, 2026.
