IPv4 to IPv6 Converter
Convert between IPv4 and IPv6 address formats — mapped, compatible, and 6to4 notation
IP Address Input
You’re configuring a dual-stack server and need to express the IPv4 address 192.168.1.1 in IPv6 mapped format (::ffff:192.168.1.1). Or you’re reading firewall logs showing ::ffff:c0a8:0101 and need to know the original IPv4 address. This tool converts between IPv4 and IPv6 formats instantly.
Why This Tool
IPv4-to-IPv6 mapping has three main formats (IPv4-mapped, IPv4-compatible, 6to4), each with different prefixes and use cases. Mental conversion requires splitting IPv4 octets into hexadecimal pairs — doable but error-prone. This tool handles all formats correctly and shows the full expanded form alongside the compressed form.
IPv4 vs IPv6
IPv4: 32-bit address written as four decimal octets (e.g., 192.168.1.1). Provides ~4.3 billion unique addresses. Exhausted — no new IPv4 blocks available.
IPv6: 128-bit address written as eight groups of four hex digits (e.g., 2001:0db8:0000:0000:0000:0000:0000:0001). Provides ~340 undecillion addresses. The long-term successor.
Conversion Formats
IPv4-Mapped IPv6
Prefix: ::ffff: followed by the IPv4 address.
IPv4: 192.168.1.1
IPv6: ::ffff:192.168.1.1
Full: 0000:0000:0000:0000:0000:ffff:c0a8:0101This is the most common format. Used by dual-stack applications to represent IPv4 connections in IPv6 notation.
IPv4-Compatible IPv6 (Deprecated)
Prefix: :: followed by the IPv4 address.
IPv4: 192.168.1.1
IPv6: ::192.168.1.1
Full: 0000:0000:0000:0000:0000:0000:c0a8:0101Deprecated by RFC 4291 in favor of IPv4-mapped addresses. Shown for reference.
6to4 Address
Prefix: 2002: followed by the IPv4 octets converted to hex.
IPv4: 192.168.1.1
6to4: 2002:c0a8:0101::Used by the 6to4 transition mechanism (RFC 3056) to automatically derive IPv6 addresses from IPv4 addresses.
How the Conversion Works
Each IPv4 octet (0–255 decimal) converts to a two-digit hexadecimal value:
| IPv4 Octet | Hex |
|---|---|
| 192 | c0 |
| 168 | a8 |
| 1 | 01 |
| 1 | 01 |
Combined: c0a8:0101. Prepend the appropriate prefix to get the full IPv6 address.
IPv6 Address Shortening Rules
- Leading zeros in each group can be omitted:
0042→42 - Consecutive groups of all zeros can be replaced with
::(once per address) - Example:
2001:0db8:0000:0000:0000:0000:0000:0001→2001:db8::1
Frequently Asked Questions
When would I need to convert IPv4 to IPv6? When configuring dual-stack servers, reading firewall logs that show IPv4-mapped IPv6 addresses, setting up IPv6 transition mechanisms, or working with APIs that accept only IPv6 format addresses.
Is ::ffff:192.168.1.1 a real IPv6 address? Yes, it’s a valid IPv6 address in IPv4-mapped format. It represents an IPv4 connection in IPv6 notation and is commonly used by applications running on dual-stack systems.
Can any IPv4 address be converted to IPv6?
Yes. Every IPv4 address can be represented in IPv6 mapped format. The reverse is not true — only addresses in the ::ffff:0:0/96 range can be converted back to IPv4.
Does this tool send my IP addresses to a server? No. All conversion is done in JavaScript in your browser. No addresses are transmitted anywhere.