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Understand the differences between IPv4 and IPv6 addressing, subnetting, and conversion.
Read the guideUnderstanding IPv4 and IPv6
IPv4 Addresses
IPv4 uses 32-bit addresses written as four decimal octets separated by dots (dotted-decimal notation).
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Format: 192.168.1.1
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Total addresses: ~4.3 billion
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Example ranges: 10.0.0.0/8, 192.168.0.0/16
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Address exhaustion led to IPv6 development
IPv6 Addresses
IPv6 uses 128-bit addresses written as eight groups of four hexadecimal digits separated by colons.
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Format: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
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Total addresses: 3.4 x 10^38
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Can be compressed: 2001:db8:85a3::8a2e:370:7334
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Built-in security and autoconfiguration
Transition Mechanisms
Dual Stack
Devices run both IPv4 and IPv6 simultaneously. This is the preferred long-term solution as it provides native support for both protocols without translation overhead.
Tunneling
IPv6 packets are encapsulated within IPv4 packets to traverse IPv4-only networks. Methods include 6to4, Teredo, and ISATAP. Useful during transition but adds overhead.
Translation (NAT64)
Translates between IPv4 and IPv6 at the network level. Allows IPv6-only clients to access IPv4-only servers. Common in mobile networks and large enterprises.
IPv6 Address Scopes
Type Prefix Scope Use Case
Global Unicast 2000::/3 Global Internet-routable addresses
Link-Local fe80::/10 Link Auto-configuration, neighbor discovery
Unique Local fc00::/7 Organization Private networks (like RFC 1918)
Multicast ff00::/8 Various One-to-many communication
Loopback ::1/128 Node Local host (like 127.0.0.1)
IPv4-Mapped ::ffff:0:0/96 N/A Dual-stack compatibility
Planning IPv6 Migration?
Our network architects design dual-stack implementations and IPv6 transition strategies.
What Is IPv4 to IPv6 Conversion
IPv4 (Internet Protocol version 4) uses 32-bit addresses providing approximately 4.3 billion unique addresses — a pool that has been exhausted since 2011. IPv6 uses 128-bit addresses, providing 340 undecillion (3.4 x 10^38) addresses — enough to assign a unique address to every atom on the surface of the Earth and still have addresses left over.
Converting and mapping between IPv4 and IPv6 addresses is essential during the ongoing global transition from IPv4 to IPv6. Organizations must support both protocols simultaneously (dual-stack), translate between them, and understand how IPv4 addresses are represented within IPv6 space.
Address Format Comparison
| Feature | IPv4 | IPv6 |
|---|---|---|
| Address length | 32 bits | 128 bits |
| Notation | Dotted decimal (192.168.1.1) | Colon hexadecimal (2001:0db8::1) |
| Address space | ~4.3 billion | ~340 undecillion |
| Header size | 20-60 bytes (variable) | 40 bytes (fixed) |
| Broadcast | Yes | No (replaced by multicast) |
| IPsec | Optional | Built-in (mandatory to implement) |
| NAT required | Typically yes | No — enough addresses for direct connectivity |
| Checksum | In header | Removed (handled by link and transport layers) |
IPv4-Mapped IPv6 Addresses
IPv4 addresses can be represented within IPv6 address space using special mapping formats:
| Type | Format | Example |
|---|---|---|
| IPv4-Mapped | ::ffff:IPv4 | ::ffff:192.168.1.1 or ::ffff:c0a8:0101 |
| IPv4-Compatible | ::IPv4 (deprecated) | ::192.168.1.1 |
| 6to4 | 2002:IPv4::/48 | 2002:c0a8:0101::/48 |
| NAT64 | 64:ff9b::IPv4 | 64:ff9b::192.168.1.1 |
Common Use Cases
- Network migration planning: Convert IPv4 address schemes to IPv6 equivalents when planning dual-stack deployments
- Firewall rule translation: Convert IPv4-based firewall rules and access control lists to their IPv6 equivalents
- DNS configuration: Set up AAAA records (IPv6) alongside A records (IPv4) for dual-stack web servers
- Application development: Ensure applications handle both address formats correctly, including storage, validation, and display
- Troubleshooting: Convert between formats when analyzing logs that mix IPv4 and IPv6 addresses
Best Practices
- Plan for dual-stack — The transition period requires supporting both IPv4 and IPv6 simultaneously. Dual-stack (native support for both protocols) is preferred over translation mechanisms.
- Use IPv4-mapped addresses correctly — ::ffff:0:0/96 is for internal use by dual-stack systems. Do not use IPv4-mapped addresses on the wire or in DNS records.
- Simplify IPv6 addresses — Use zero compression (::) and remove leading zeros for readability. 2001:0db8:0000:0000:0000:0000:0000:0001 becomes 2001:db8::1.
- Update applications and libraries — Ensure your code uses address-family-independent APIs (getaddrinfo instead of gethostbyname) to support both IPv4 and IPv6.
- Test IPv6 connectivity — Many networks still lack full IPv6 support. Test your services over IPv6-only connections to ensure they work without IPv4 fallback.
Frequently Asked Questions
Common questions about the IPv4 to IPv6 Converter
This tool converts IP addresses between IPv4 and IPv6 formats. For IPv4 addresses, it generates IPv4-mapped IPv6 addresses in both dotted and hexadecimal notation, as well as 6to4 transition addresses. For IPv6 addresses, it provides full and compressed forms, identifies the address type, and extracts embedded IPv4 addresses when present.
An IPv4-mapped IPv6 address represents an IPv4 address within the IPv6 address space using the format ::ffff:a.b.c.d. This format is defined in RFC 4291 and is commonly used by dual-stack applications that need to handle both IPv4 and IPv6 connections through a single socket interface.
A 6to4 address is a transition mechanism defined in RFC 3056 that allows IPv6 packets to be transmitted over an IPv4 network. These addresses use the 2002::/16 prefix followed by the IPv4 address encoded in hexadecimal. While useful for transition scenarios, 6to4 is being deprecated in favor of native IPv6 connectivity.
The tool identifies multiple IPv6 address types including Global Unicast (2000::/3), Link-Local (fe80::/10), Unique Local Address (fc00::/7), Multicast (ff00::/8), Loopback (::1), IPv4-Mapped, 6to4 Transition, Teredo Tunneling, and Documentation addresses. It also indicates the scope such as global, link-local, or organization-local.
Full form IPv6 shows all eight 16-bit groups with leading zeros, such as 2001:0db8:0000:0000:0000:0000:0000:0001. Compressed form removes leading zeros from each group and replaces the longest consecutive sequence of all-zero groups with ::, resulting in 2001:db8::1. Both represent the same address.
No, all conversions happen entirely in your browser using JavaScript. Your IP addresses are never transmitted to any server. This makes the tool safe for analyzing internal network addresses or sensitive infrastructure information without any privacy concerns.
ℹ️ Disclaimer
This tool is provided for informational and educational purposes only. All processing happens entirely in your browser - no data is sent to or stored on our servers. While we strive for accuracy, we make no warranties about the completeness or reliability of results. Use at your own discretion.