IPv4/IPv6 Converter
Convert an IPv4 address to IPv6 and vice versa.
IP Converter: convert an IPv4 address to IPv6 and vice versa
Are you looking to convert an IPv4 address to IPv6 or perform the opposite operation? An IP address can be represented in different formats depending on the Internet protocol version used.
With PleaseTools' IP Converter, you can enter an IP address and get its representation in the format supported by the tool. The system automatically detects whether it is an IPv4 or IPv6 address and performs the corresponding conversion.
This tool can be useful for developers, system administrators, network engineers, students, and anyone working with IP addresses.
What is an IP address?
An IP address is an address used to identify a network interface in communications using the Internet protocol.
The two main versions encountered are:
- IPv4, Internet Protocol version 4;
- IPv6, Internet Protocol version 6.
IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses.
However, these two protocols use very different representations.
What is an IPv4 address?
IPv4 is the fourth version of the Internet protocol and remains widely used on the Internet.
An IPv4 address consists of 32 bits, typically represented as four decimal numbers separated by dots.
For example:
192.168.0.1
Each number corresponds to a byte and can take a value between 0 and 255.
Thus an IPv4 address contains four groups:
192 . 168 . 0 . 1
This format is called dotted decimal notation.
Some IPv4 address examples
8.8.8.8
1.1.1.1
192.168.1.1
10.0.0.1
172.16.0.1
The last addresses in this list belong to private address spaces and are commonly used in local networks.
What is an IPv6 address?
IPv6 is the sixth version of the Internet protocol.
It was specifically designed to address the limitation of the number of addresses available with IPv4.
An IPv6 address uses 128 bits and is usually represented in hexadecimal notation, with groups separated by colons.
Example:
2001:db8:85a3:0000:0000:8a2e:0370:7334
A full IPv6 address contains eight groups of 16 bits.
Each group can contain up to four hexadecimal characters:
2001
db8
85a3
0000
0000
8a2e
0370
7334
Hexadecimal characters range from 0 to 9 and from a to f.
Why was IPv6 created?
One of the main limitations of IPv4 is its address space.
With 32 bits, IPv4 theoretically has about 4.3 billion addresses.
That may seem huge, but the growth of the Internet has generated a considerable demand for IP addresses: computers, smartphones, servers, connected devices, industrial equipment, cloud infrastructures, etc.
IPv6 uses 128 bits, providing a considerably larger address space.
The difference is significant:
IPv4 : 32 bits
IPv6 : 128 bits
Thus IPv6 can address an extremely large number of network interfaces.
How to convert an IP address with PleaseTools?
Using IP Converter is intentionally simple.
Step 1: enter the IP address
In the "IP address to convert" field, enter the address you want to convert.
For example:
192.168.0.1
Step 2: validate
Click the "Validate" button.
The tool automatically analyzes the entered address to determine whether it is an IPv4 or IPv6 address.
Step 3: retrieve the result
Once the type is identified, PleaseTools performs the corresponding conversion and displays the result.
Therefore, it is not necessary to manually select IPv4 → IPv6 or IPv6 → IPv4.
IPv4 and IPv6 conversion: beware the term “conversion”
It is important to understand that an IPv4/IPv6 conversion is not always a simple mathematical transformation from one address to another.
IPv4 and IPv6 are two different protocols.
An IPv4 address like:
192.168.0.1
does not automatically have a unique equivalent IPv6 address that could be used everywhere on the Internet.
Depending on the mechanism used, an IPv4 address can be represented in various IPv6 formats or be used in an IPv4/IPv6 transition architecture.
Thus you must distinguish:
- representation conversion;
- IPv4-mapped IPv6 address;
- transition mechanisms;
- IPv4/IPv6 tunnels;
- protocol translation;
- native IPv6 addressing.
This distinction is particularly important for developers and network administrators.
IPv4-mapped IPv6 address
A very common special case is representing an IPv4 address as an IPv4-mapped IPv6 address.
The general format is:
::ffff:IPv4
For example, the address:
192.168.0.1
can be represented as:
::ffff:c0a8:1
This representation does not mean the device suddenly has a new native IPv6 connection.
It is a representation used especially in some network implementations and applications to represent an IPv4 address within an IPv6 address space.
Why do developers use IPv4 and IPv6?
Modern applications sometimes need to work with both protocols.
A web server, for example, may receive connections from:
IPv4
192.0.2.10
or:
IPv6
2001:db8::10
An application that systematically assumes all IP addresses contain four dot‑separated numbers may therefore encounter problems when it receives an IPv6 address.
This is particularly important for:
- web applications;
- APIs;
- servers;
- authentication systems;
- logs;
- firewalls;
- databases;
- IP geolocation systems.
IPv4 in a PHP application
When a PHP application retrieves a client's IP address, it may receive either an IPv4 or an IPv6 address.
Therefore, it is preferable not to write code that systematically assumes this format:
192.168.1.10
An IPv6 address can be much longer:
2001:db8:85a3::8a2e:370:7334
Developers therefore need to account for both formats when storing or handling IP addresses.
PHP provides functions to validate and manipulate IP addresses, such as filter_var().
$ip = '192.168.0.1';
if (filter_var($ip, FILTER_VALIDATE_IP)) {
echo 'Valid IP address';
}
The same logic can be used with an IPv6 address.
IPv4 and IPv6 in databases
Storing an IP address in a database also deserves particular attention.
A column designed only for IPv4 representation can become problematic when an application starts accepting IPv6.
Therefore, it is preferable to design applications taking both protocols into account from the start.
In a Laravel system, for example, IP addresses can be stored using mechanisms suitable for both IPv4 and IPv6 values rather than assuming all addresses will have the same length.
This concerns, in particular:
- logs;
- users;
- sessions;
- login attempts;
- white lists;
- security rules;
- traffic statistics.
IPv4 and IPv6 in logs
Log files constitute another common case.
A server may log:
192.168.1.20
but also:
2001:db8::1234
An application that systematically splits an address with explode('.', $ip) may therefore work with IPv4 but produce incorrect results with IPv6.
You should always treat the address as an IP value, not as a simple string with a fixed format.
IPv4 and IPv6 in security systems
IP addresses are frequently used in security mechanisms.
For example:
- allow an address;
- block an address;
- limit login attempts;
- create a whitelist;
- log connections;
- apply firewall rules.
With IPv6, however, you must take into account the notation and representation of addresses.
A naive string comparison can also lead to unexpected results when different representations of the same address are possible.
For sensitive applications, it is preferable to use functions or libraries specialized in IP address manipulation.
Does IPv6 always use eight full groups?
No.
An IPv6 address can be abbreviated.
For example:
2001:0db8:0000:0000:0000:0000:0000:0001
can be represented in a shorter form:
2001:db8::1
Leading zeros in a group can be removed.
Multiple consecutive groups composed solely of zeros can also be compressed with ::.
This possibility explains why two textual representations of an IPv6 address can differ while still referring to the same address.
Why does an IPv6 address seem much longer?
It is simply due to the size of the address space.
IPv4:
192.168.1.1
IPv6:
2001:db8:85a3::8a2e:370:7334
IPv4 uses 32 bits.
IPv6 uses 128 bits.
Therefore, many more characters are needed to represent an IPv6 address.
IP Converter for development testing
Developers can use an IP converter to quickly check an application's behavior with different address representations.
For example, when developing a logging system, it may be useful to test:
127.0.0.1
then:
::1
127.0.0.1 is the commonly used IPv4 loopback address, while ::1 corresponds to the IPv6 loopback.
Testing both allows detection of hidden assumptions in the code.
IPv4 and IPv6 in local networks
Local networks can also use IPv4, IPv6, or both.
A computer may, for example, have simultaneously:
IPv4:
192.168.1.20
and:
IPv6:
fe80::1234:5678:abcd:ef01
This situation is common in environments using dual stack, where IPv4 and IPv6 operate simultaneously.
Thus, IPv4 and IPv6 should not necessarily be considered mutually exclusive choices.
IP Converter is not a subnet calculator
You should also distinguish an IP converter from a subnet calculator.
A subnet calculator can, in particular, determine:
- the network;
- the broadcast;
- the mask;
- the CIDR prefix;
- the address range;
- the number of hosts.
IP Converter addresses a different problem: working with the representation of an IPv4 or IPv6 address.
These tools can therefore be complementary.
Common mistakes with IP addresses
Confusing public IP with private IP
An address like:
192.168.1.10
is a common private address.
It does not necessarily correspond to the address visible from the Internet.
Assuming an IPv4 always has an equivalent IPv6
IPv4 and IPv6 are different protocols.
Thus, a simple IPv4 address cannot be converted into a universally equivalent IPv6 address in all contexts.
Assuming IPv6 can always be compared as a string
Two textual representations of the same IPv6 address can differ due to compression and zero suppression possibilities.
For reliable comparison, you must normalize or use specialized functions.
Storing only IPv4 addresses
An application designed today should avoid assuming all connections will use IPv4.
IPv6 support should be considered from the design stage when the application handles IP addresses.
Frequently asked questions on IPv4 and IPv6 conversion
How to convert an IPv4 address to IPv6?
Enter the IPv4 address in IP Converter, then click Validate. The tool automatically detects the address type and performs the conversion defined by its representation mechanism.
How to convert an IPv6 address to IPv4?
Enter the IPv6 address in the tool's field then click Validate. If the address matches a format compatible with the reverse conversion offered by the tool, the result is displayed.
Are an IPv4 address and an IPv6 address equivalent?
No. IPv4 and IPv6 are different protocols with different address spaces.
How many bits does an IPv4 address contain?
An IPv4 address contains 32 bits.
How many bits does an IPv6 address contain?
An IPv6 address contains 128 bits.
Why is IPv6 necessary?
IPv6 was specifically developed to have a much larger address space than IPv4.
Can an IPv6 be written in multiple forms?
Yes. IPv6 allows omission of non‑significant zeros and compression of sequences of zero groups with ::.
What is the IPv4 localhost address?
The most well‑known IPv4 loopback address is:
127.0.0.1
What is the IPv6 localhost address?
The IPv6 loopback address is:
::1
Does IP Converter provide location information for an address?
No. Converting an IP address and geolocating it are two different operations. To estimate an address's location, use an IP geolocation tool.
Conclusion
IPv4 and IPv6 are two major versions of the Internet protocol, but they use very different formats and address spaces.
IPv4 uses 32-bit addresses generally represented in decimal form, while IPv6 uses 128-bit addresses represented in hexadecimal notation.
Handling these addresses has become essential for developers and network administrators, especially with the progression of IPv6.