IPv4 to IPv6 Converter
Write an IPv4 address in IPv6 form. The converter shows the IPv4-mapped address that software uses, the 6to4 prefix and the NAT64 address, each in the notations you are likely to need, and it works in the other direction for IPv6 addresses that carry an IPv4 address inside them.
- Runs in your browser
- No sign-up
- Free to use
Enter an IPv4 address to see its IPv6 representations, or an IPv6 address to extract the IPv4 address embedded in it.
How to use IPv4 to IPv6 Converter
- Type or paste an IPv4 address such as 192.168.1.10.
- Read the IPv4-mapped address at the top and the other formats in the table.
- Use the copy button next to the notation you need.
- To go the other way, enter an IPv6 address; any embedded IPv4 address is extracted and explained.
IPv4 to IPv6 Converter features
IPv4-mapped addresses
In dotted (::ffff:192.168.1.10), hexadecimal and fully expanded notation.
6to4 prefix
The /48 network that the 6to4 mechanism assigns to a public IPv4 address.
NAT64 address
The address under the well-known prefix 64:ff9b::/96 that IPv6-only clients use to reach an IPv4 host.
Reverse extraction
Finds the IPv4 address inside mapped, NAT64, 6to4 and Teredo addresses.
Other notations
Decimal, hexadecimal and binary forms of the IPv4 address and its reverse DNS name.
Honest explanations
States clearly that these are representations and transition formats, not a native IPv6 address for the host.
When to use IPv4 to IPv6 Converter
- Understanding log entries that show clients as ::ffff:203.0.113.5.
- Writing firewall or application rules that must match IPv4 clients on a dual-stack socket.
- Configuring or debugging NAT64 and DNS64 in an IPv6-only network.
- Studying IPv6 transition mechanisms for a certification exam.
IPv4 to IPv6 Converter FAQ
Can an IPv4 address really be converted to IPv6?
Not in the sense of obtaining a working IPv6 address for the same host. IPv4 and IPv6 are separate address spaces, and a device needs its own IPv6 address from its network. What can be converted is the notation: IPv6 reserves ranges in which an IPv4 address is embedded for specific purposes, and this tool produces those.
What is an IPv4-mapped IPv6 address?
An address of the form ::ffff:a.b.c.d. Operating systems use it on dual-stack sockets so that one IPv6 socket can also accept IPv4 connections; the IPv4 peer then appears in mapped form. It is never sent over the network as an IPv6 destination.
Why do my server logs show ::ffff: before client addresses?
The server listens on an IPv6 socket that also handles IPv4. Connections arriving over IPv4 are reported in mapped form. The part after ::ffff: is the client's ordinary IPv4 address.
What is 6to4?
A transition mechanism that gave every public IPv4 address a /48 IPv6 network under 2002::/16, built by placing the IPv4 address in hexadecimal after the 2002 prefix. Public 6to4 relays have been phased out, so it is mostly of historical and educational interest.
What is NAT64?
A gateway that lets IPv6-only clients reach IPv4 servers. The client connects to an IPv6 address formed from a NAT64 prefix, commonly 64:ff9b::/96, plus the IPv4 address, and the gateway translates the traffic. Mobile networks use this widely.
Are ::ffff:192.168.1.10 and ::ffff:c0a8:10a the same?
Yes. The last 32 bits of an IPv6 address may be written either as two hexadecimal groups or in dotted IPv4 notation. Both spellings denote the same address.
How IPv4 addresses appear inside IPv6
IPv6 was designed to coexist with IPv4 for a long time, and several of its address ranges exist only to carry IPv4 addresses. Each range has a different job, which is why a single “conversion” does not exist. Knowing which format you are looking at tells you which mechanism is in play.
The mapped range, ::ffff:0:0/96, is an internal convention between applications and the operating system. A web server that opens one IPv6 socket can serve both protocols, and it sees IPv4 visitors as mapped addresses. This is the form people most often need, for example when a configuration file or a database column expects IPv6 syntax but the actual peer is IPv4.
NAT64 addresses solve the opposite problem. In a network that has no IPv4 at all, a DNS64 resolver invents an IPv6 address for sites that only have IPv4 by attaching the IPv4 address to a NAT64 prefix. The client connects to it like to any IPv6 destination, and a translator at the network edge converts the packets. If you see addresses starting with 64:ff9b:: in a trace, this is what is happening.
6to4 and Teredo were earlier attempts to tunnel IPv6 across the IPv4 internet. Both embed IPv4 addresses, 6to4 directly after the 2002 prefix and Teredo in an obscured form, and both have largely been retired in favour of native IPv6. They still appear in older documentation and exam material, so the converter decodes them when you enter such an address.