Free IPv4 to IPv6 Converter
Convert an IPv4 address into its IPv6 representations — mapped, compatible and 6to4 — and see the expanded and compressed forms. Useful for network configuration, dual-stack setups and documentation.
The reverse direction is handled by IPv6 to IPv4, and the Subnet / CIDR Calculator works out the network around a single address.
How to use the IPv4 to IPv6
- 1 Enter an IPv4 address such as 192.0.2.1.
- 2 Read the IPv6 forms — the IPv4-mapped form, the 6to4 form and the hex-grouped equivalent.
- 3 Compare the notations to see how the same 32 bits are written in IPv6.
- 4 Use the reverse direction to extract an IPv4 address from a mapped IPv6 address.
How to Use
Enter any valid IPv4 address (or an IPv4-mapped IPv6 address to convert back) and every equivalent IPv6 form is shown instantly.
- IPv4-mapped IPv6 (::ffff:192.0.2.1)
- IPv4-compatible IPv6 (::192.0.2.1)
- 6to4 (2002::/16) form
- Expanded and compressed full notation
- Reverse: IPv4-mapped IPv6 back to IPv4
About IPv6 transition forms
Because IPv4 and IPv6 are not directly compatible, several mapping schemes exist. IPv4-mapped addresses (::ffff:a.b.c.d) let an IPv6 socket represent an IPv4 peer. 6to4 (2002:xxxx:xxxx::/48) embeds the IPv4 address to route through IPv6 networks.
Frequently asked questions
What is an IPv4-mapped IPv6 address?
An address in the form ::ffff:192.0.2.1. It carries a real IPv4 address inside an IPv6 one so a dual-stack system can represent both with a single data type. It does not make the IPv4 address routable over IPv6 — it is a notation, not a translation.
Does converting IPv4 to IPv6 make my address work on IPv6 networks?
No. The two protocols are not interoperable by conversion alone. Real connectivity needs dual-stack hosts, NAT64 with DNS64, or a tunnel — which is why the mapped form is mostly seen in software, not on the wire.
Why does IPv6 use hexadecimal groups?
Because 128 bits would be unwieldy in decimal. IPv6 writes eight groups of four hex digits, and allows :: to stand in for one run of zero groups — so 2001:0db8:0000:0000:0000:0000:0000:0001 becomes 2001:db8::1.
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