IPv4 to IPv6 converter
Write any IPv4 address in its standard IPv6 forms (IPv4-mapped, NAT64 and 6to4) and learn which one you actually need.
192.0.2.33 · Documentation (TEST-NET-1)
| Form | Address | Used for |
|---|---|---|
| IPv4-mapped | ::ffff:192.0.2.33 ::ffff:c000:221 | How dual-stack sockets represent IPv4 peers (logs, getpeername). |
| IPv4-mapped (expanded) | 0000:0000:0000:0000:0000:ffff:c000:0221 | Same address, fully written out. |
| NAT64 well-known | 64:ff9b::192.0.2.33 64:ff9b::c000:221 | What DNS64 returns on IPv6-only mobile networks. |
| 6to4 prefix | 2002:c000:0221::/48 | Legacy tunnel prefix derived from a public IPv4 (deprecated). |
| IPv4-compatible | ::192.0.2.33 ::c000:221 | Deprecated by RFC 4291; do not use. |
IPv4 and IPv6 are separate addresses
A device on a dual-stack network has an IPv4 address and one or more IPv6 addresses, assigned independently. There is no formula from one to the other. The forms above exist so software and transition mechanisms can carry an IPv4 address in an IPv6-shaped field. To see whether your own connection has IPv6, check what is my IP; to plan IPv6 subnets, use the IPv6 subnet calculator.
Questions people ask
Can you convert an IPv4 address to IPv6?
Not in the sense of getting "your IPv6 address"; that is assigned separately by your ISP. What you can do is write an IPv4 address inside IPv6 notation, and several standard forms exist for specific transition mechanisms, listed above.
What is an IPv4-mapped IPv6 address?
::ffff:a.b.c.d (RFC 4291). Dual-stack operating systems use it internally so an IPv6 socket can accept IPv4 connections; you'll see it in server logs as ::ffff:203.0.113.5. It never appears on the wire.What is 64:ff9b::/96?
The well-known NAT64 prefix (RFC 6052). On IPv6-only networks (many mobile carriers), DNS64 synthesises AAAA records inside it so IPv6-only clients can reach IPv4-only servers through a NAT64 gateway.
Is 6to4 still used?
Rarely. 6to4 (2002::/16) was deprecated for new deployments by RFC 7526 in 2015 because of unreliable public relays. It's shown for recognising old addresses.