IP Tools
What is my IPv4 address?
Check the IPv4 address your connection is using and confirm that IPv4 connectivity is working.
Your IPv4 address
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What is IPv4?
IPv4 — Internet Protocol version 4 — is the addressing scheme the internet has run on since
1983. Every IPv4 address is 32 bits long, written as four numbers from 0 to 255 separated by
dots. 203.0.113.42 is a valid IPv4 address; 203.0.113.256 is not, because
256 does not fit in eight bits.
Thirty-two bits allows about 4.3 billion unique addresses. That seemed limitless when the internet connected a few hundred research machines. It is not remotely enough for a world with billions of phones, laptops, servers and connected appliances, which is the core problem IPv6 exists to solve.
How to read an IPv4 address
An address splits into a network part and a host part. The boundary is set by the subnet mask,
usually written in CIDR notation as a suffix: 192.168.1.0/24 means the first 24 bits
identify the network and the remaining 8 bits identify hosts on it — 254 usable addresses, since
the first and last are reserved for the network and broadcast addresses.
Reserved IPv4 ranges worth knowing
-
10.0.0.0/8,172.16.0.0/12,192.168.0.0/16— private networks, not routable on the internet. -
127.0.0.0/8— loopback.127.0.0.1always means "this machine". 169.254.0.0/16— link-local, self-assigned when DHCP fails.-
100.64.0.0/10— carrier-grade NAT, used by providers to share public addresses. 224.0.0.0/4— multicast.
Why your IPv4 address changes
Most residential connections use dynamic addressing: the provider leases you an address for a period and may issue a different one when the lease expires or your router reconnects. A static address that never changes is normally a paid business option, and is what you need when running a server that others connect to by address.
Your address also changes whenever you change networks — moving from home Wi-Fi to mobile data puts you on an entirely different provider's network with a different address.
IPv4 and carrier-grade NAT
Because IPv4 space ran out, many providers now place customers behind carrier-grade NAT, where
hundreds or thousands of subscribers share one public address. If your router reports an
address in 100.64.0.0/10 while this page shows something different, you are behind
CGNAT. It is usually invisible for browsing, but it breaks inbound connections — port forwarding,
self-hosted servers and some peer-to-peer applications will not work.
This is one of the practical reasons to care about IPv6: it restores end-to-end addressing. You can check whether your connection supports it with the IPv6 checker, or look up the details of any address with IP Lookup.
Frequently asked questions
What is my IPv4 address?
Your IPv4 address is the four-number address your internet provider assigns to your connection, written as four values from 0 to 255 separated by dots, such as 203.0.113.42. The checker above shows the IPv4 address that websites see when you connect to them.
What is the difference between a public and a private IPv4 address?
A public IPv4 address is unique on the internet and is the one shown above. A private address is used only inside your own network and is not routable on the internet. Private ranges are 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. If the address on your device starts with one of those, you are looking at a private address handed out by your router.
Why do several devices in my home share one IPv4 address?
Because of Network Address Translation. Your router holds a single public IPv4 address and multiplexes every device behind it, rewriting addresses and ports as traffic passes through. That is why every device in your home shows the same public IPv4 address here.
Are we running out of IPv4 addresses?
Yes, and it already happened. IPv4 has about 4.3 billion addresses and the regional registries exhausted their free pools between 2011 and 2019. Providers now stretch the remaining space with carrier-grade NAT, where thousands of customers share a single public address, and addresses are traded on a secondary market. IPv6 is the long-term fix.
Is it safe for a website to see my IPv4 address?
It is unavoidable — a site cannot send you a response without knowing where to send it. The address identifies your connection, not you. It reveals your provider and approximate region, but not your name or precise location.