IPv4 to IPv6 converter
Convert an IPv4 address to its IPv6-mapped, compatible and 6to4 forms.
Runs 100% in your browserHow to convert IPv4 to IPv6
- Enter an IPv4 address. Type a dotted-decimal IPv4 like 203.0.113.5.
- Read the IPv6 forms. Mapped, compatible, fully expanded and 6to4 prefix are shown.
IPv4 in an IPv6 world
Dual-stack hosts expose IPv4 traffic to applications using the IPv4-mapped form
::ffff:a.b.c.d. The IPv4-compatible form (::a.b.c.d) was deprecated in
RFC 4291. 6to4 tunnels (RFC 3056) gave every public IPv4 a deterministic
2002::/16-prefixed /48 — useful to recognise in old configurations but not used
much for new deployments. This tool shows all three so you can plug whichever your tooling
expects.
Frequently asked questions
- IPv4 addresses do not have a single canonical IPv6 form. The common encodings are the IPv4-mapped IPv6 address (::ffff:a.b.c.d) used by dual-stack sockets, the older IPv4-compatible form (::a.b.c.d), and 6to4 tunnels (2002:a.b:c.d::/48).
- The IPv4-mapped IPv6 address, RFC 4291 §2.5.5.2. Operating systems use it to expose IPv4 connections through an IPv6 API. The low 32 bits are the IPv4 address; the bits above are zeroed.
- A transition tunnel where any public IPv4 address gets a /48 IPv6 block as 2002:WWXX:YYZZ::/48 (where WWXX:YYZZ is the IPv4 in hex). Largely deprecated, but you may still see it in legacy configs.
- No. The conversion is pure math in your browser.