IPv6 to IPv4 Converter
Give our IPv6 to IPv4 converter an address and it returns the IPv4 embedded inside it, when the address uses a supported format. Not every IPv6 address carries one. The converter checks for five supported formats that can contain an IPv4 address, tells you which one you pasted, and does the whole job in your browser so nothing you paste leaves your machine.
How to Convert IPv6 to IPv4
- Enter your IPv6 address in the field above.
- Press Convert to IPv4. The tool identifies which address type you pasted and reads the IPv4 out of it.
- Copy your result. Alongside the IPv4 address you get its type, so you know which addressing or transition mechanism produced the embedded IPv4. 6to4 results are labelled generically rather than by name; the other four types are labelled as shown in the table below.
Addresses can be written short or fully expanded. Both work.
Which IPv6 Addresses Can Be Converted to IPv4
Most tools that convert IPv6 to IPv4 addresses, sometimes searched as convert ip6 to ip4, focus on mapped and 6to4 forms only. Ours supports five formats, because IPv4 addresses ended up embedded in more places than those two. Each one comes from a different addressing or transition mechanism. This is not an exhaustive list of every IPv4-embedding format that has ever existed, it is the five our converter supports.
| Address type | Starts with | What it usually means |
|---|---|---|
| IPv4-mapped | ::ffff: | A dual stack machine noting down an IPv4 visitor |
| 6to4 | 2002: | A 6to4 address containing the IPv4 address used in its prefix |
| NAT64 | 64:ff9b::/96 | An address using the NAT64 Well-Known Prefix |
| IPv4-compatible | :: then the address | An early transition format, now deprecated |
| Teredo | 2001:0000: | A client tunnelling out from behind NAT |
Teredo returns extra detail. The format stores the client's mapped IPv4 address and mapped UDP port in obfuscated form, and our converter decodes them for you.
IPv6 to IPv4 Conversion Examples
Paste any of these to see how each type reads out. The examples use IPv4 addresses from the documentation ranges defined in RFC 5737, so none of them belong to a real host or server.
| Input | Result |
|---|---|
| ::ffff:c000:0201 | 192.0.2.1, IPv4-mapped |
| ::ffff:192.0.2.1 | 192.0.2.1, IPv4-mapped |
| 2002:c000:0237:: | 192.0.2.55, 6to4-style documentation example |
| 64:ff9b::c633:6417 | 198.51.100.23, NAT64 |
| ::c633:6407 | 198.51.100.7, IPv4-compatible |
| 2001:0000:cb00:710a:8000:63bf:34ff:8ed2 | 203.0.113.45, Teredo |
In the Teredo example, the encoded fields decode to server address 203.0.113.10 and port 40000, which is the part you cannot work out by eye. As with the other rows, these values sit in documentation space and do not point at a real Teredo server.
Why Some IPv6 Addresses Cannot Be Converted to IPv4
If the tool tells you an address holds no IPv4, that is the correct answer rather than a failure. IPv4 has 2^32 possible addresses, about 4.3 billion. IPv6 has 2^128, a number so much larger that most IPv6 addresses do not contain an embedded IPv4 address at all. An IPv4 address can appear inside an IPv6 address when an addressing or transition mechanism defines an IPv4-embedded format. The five formats above are the ones this converter supports, not a complete list of every mechanism that has ever existed. Everyday addresses starting fe80: or fd00: are plain IPv6 addresses with nothing tucked inside.
Our converter says so in plain words rather than returning a number that looks believable and is wrong.
Reading an address that uses the NAT64 well-known prefix is not the same as running NAT64. The embedded IPv4 address represents an address in the IPv4 namespace, typically the destination in common NAT64 deployments, and it is not necessarily the client that originated the connection. Teredo works differently: it encodes the client's mapped IPv4 address and UDP port in obfuscated form. Either way, the converter only extracts the values already encoded in the address, it does not perform NAT64 translation or establish who generated the traffic.
IPv6 to IPv4 Converter Use Cases
Your access logs are the most common reason people land here. A log holds ::ffff:198.51.100.7 while every filter you wrote expects 198.51.100.7. One visitor, two spellings, and rules that quietly miss.
Firewall rules fail the same way. You banned an IPv4 address and the traffic kept coming. If your server hands that address to your code in mapped form, the ban never matched it in the first place.
NAT64 and Teredo addresses both encode an IPv4 address inside an IPv6 one, though what that address represents differs. Extracting it, and for Teredo the mapped port as well, gives you a concrete address to check against your own records instead of an opaque IPv6 string.
A 2002: address contains the IPv4 address associated with its 6to4 prefix, which can help when documenting inherited equipment configured long before you got there. It does not confirm the tunnel is still active.
Frequently Asked Questions
For location, ISP, and network data on any address you decode, see our IP Geolocation API.