Subnetcalculator

IPv6 to IPv4 Converter

Paste an IPv6 address to extract its embedded IPv4 address (mapped, 6to4, NAT64, compatible) — or paste an IPv4 address to see all of its IPv6 embeddings. Runs entirely in your browser.

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How IPv4 addresses are embedded in IPv6

IPv6 was not designed to be backward-compatible with IPv4 at the address level — a 128-bit address cannot generally be squeezed into 32 bits. Instead, several transition mechanisms embed a full IPv4 address inside an IPv6 address at a known bit position, so gateways and dual-stack software can recover it.

Format Prefix IPv4 location Example
IPv4-mapped::ffff:0:0/96Last 32 bits::ffff:192.168.1.1
NAT64 well-known64:ff9b::/96Last 32 bits64:ff9b::8.8.8.8
6to4 (historic)2002::/16Bits 17-482002:c000:204::1
IPv4-compatible (deprecated)::/96Last 32 bits::192.0.2.4

Frequently asked questions

How do I find the IPv4 address from an IPv6 address?

Only IPv6 addresses that embed an IPv4 address contain one. Check the prefix: IPv4-mapped addresses look like ::ffff:a.b.c.d (last 32 bits are the IPv4 address), NAT64 addresses start with 64:ff9b::, and 6to4 addresses start with 2002: (the IPv4 address is encoded in bits 17-48 as hex). Paste the address into this converter and it identifies the embedding type and extracts the IPv4 address — or tells you clearly when there is none.

What is an IPv4-mapped IPv6 address?

An IPv4-mapped IPv6 address (::ffff:0:0/96, e.g. ::ffff:192.168.1.1) represents an IPv4 host inside the IPv6 address space. Dual-stack operating systems use them so a single IPv6 socket can also accept IPv4 connections — which is why they frequently appear in server logs. The last 32 bits are the real IPv4 address.

Can every IPv6 address be converted to IPv4?

No. IPv6 addresses are 128 bits and IPv4 addresses are 32 bits, so there is no general mapping — the vast majority of IPv6 addresses (like 2001:db8::1) simply have no IPv4 equivalent. Conversion is only possible for the special transition formats that deliberately embed an IPv4 address: IPv4-mapped, NAT64, 6to4, and the deprecated IPv4-compatible format. Any tool that claims to convert an arbitrary IPv6 address to IPv4 is making the answer up.

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