Guide
What is an IP address?
A clear, jargon-free explanation of what an IP address is, how your ISP assigns one, what it reveals about you, and why it changes.
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What an IP address actually is
An Internet Protocol address is the postal address of a device on a network. Every packet of data leaving your computer carries a source address and a destination address, and routers along the way use those numbers to decide where to forward the packet next. Without one, a server would have no idea where to send the page you requested.
There are two formats in use today. An IPv4 address is four numbers from 0 to 255 separated by dots — 203.0.113.45. An IPv6 address is eight groups of hexadecimal digits separated by colons — 2001:0db8:85a3::8a2e:0370:7334. Most modern connections have both at the same time.
See yours right now: the home page checker shows your live IPv4 and IPv6 addresses along with the ISP and location that websites can see.
How you get your IP address
You do not choose your public IP — your internet service provider does. When your router connects, it requests configuration from the ISP and is handed an address from a pool the ISP has been allocated by a regional internet registry such as ARIN, RIPE NCC or APNIC.
Inside your home, your router then runs its own private network. Your laptop, phone and TV each get a private address like 192.168.1.24, and the router translates all of their traffic onto the single public address using network address translation (NAT). That is why every device in your house shows the same public IP on this site.
What your IP reveals about you
| Visible to any website | Not visible |
|---|---|
| Approximate city or region | Your street address |
| Country and time zone | Your name or account details |
| Your ISP and its ASN | What is stored on your device |
| Whether you are on mobile, broadband or a datacentre | Which person in the household is browsing |
| Whether the address is flagged as a proxy or VPN | Your browsing history on other sites |
That is enough for advertisers to target you by region, for streaming services to enforce licensing, and for shops to show local pricing. Only your ISP can connect an address to a subscriber, and normally only a court order will compel them to.
Dynamic vs static addresses
Most residential connections use a dynamic address on a DHCP lease. It may stay the same for weeks, then change after a modem reboot or a maintenance window. A static address is permanently reserved for you — usually a paid business option, and essential if you host a mail server, run a VPN endpoint or need a fixed firewall allowlist entry.
Why you may share an IP with strangers
IPv4 ran out of free addresses years ago, so many ISPs — mobile networks especially — put hundreds of customers behind one public address using carrier-grade NAT. If your router's WAN address starts with 100.64 to 100.127, you are behind CGNAT. Incoming connections and port forwarding will not work, and a neighbour's behaviour can get "your" IP rate-limited. The long-term fix is IPv6, which gives every device a globally unique address again.
Quick checklist
- Your public IP is assigned by your ISP and shared by every device in your home.
- It reveals your rough location, ISP and network type — not your identity.
- It probably changes from time to time unless you pay for a static address.
- A VPN replaces it with a datacentre address, which our checker will flag.
- Check it any time on the public IP checker, or investigate a third-party address with the IP lookup tool.
Frequently asked questions
Is my IP address personal data?
Under the GDPR and similar laws, an IP address is treated as personal data because it can be combined with ISP records to identify a person. That is why privacy policies must disclose IP logging.
Can I change my IP address?
Yes. Restarting your router often gets you a new dynamic address, connecting through a VPN or proxy replaces it instantly, and switching to mobile data gives you a different one entirely.
Does an IP address identify a device or a connection?
A public IP identifies your connection, not one device. Everything behind your router shares it. Private addresses inside your network identify individual devices.
Keep reading
Check any other IP address
Investigating a suspicious login, a spam email header or a server log entry? Run any IPv4 or IPv6 address through the same geolocation and proxy checks.