Ipv4 Ipv6 Converter

Fast, accurate and free online ipv4 ipv6 converter tool running directly in your browser.

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IPv4 to IPv6 Converter - Network Address Calculations

IPv4 (32-bit) and IPv6 (128-bit) are two versions of the Internet Protocol. The converter converts addresses between formats, calculates binary and decimal values, determines the subnet range with CIDR notation and helps to understand the IP addressing structure.

IPv4 IPv6 converter IP address calculator CIDR network calculator convert IP to IPv6

IPv4 and IPv6 format

IPv4: 32 bits = 4 octets in decimal notation. 192.168.1.1. Range: 0.0.0.0 – 255.255.255.255. Max 4.3 billion addresses. IPv6: 128 bits = 8 groups of 4 hex. 2001:0db8:85a3:0000:0000:8a2e:0370:7334. Shortcut: :: replaces a string of zeros. ::1 = localhost. Range: 3.4 × 10³⁸ addresses. Conversion: IPv4-mapped IPv6: ::ffff:192.168.1.1.

CIDR notation – subnet masks

CIDR: a.b.c.d/n – n is the number of mask bits. /24 = 255.255.255.0 (256 addresses, 254 hosts). /16 = 255.255.0.0 (65536 addresses). /32 = one host. /0 = entire internet. Network address: AND address with mask. Broadcast: OR the address with the mask reversed. Hosts = 2^(32-n) - 2. Example: 192.168.1.0/24: network 192.168.1.0, broadcast 192.168.1.255, hosts .1-.254.

Private IP Ranges (RFC 1918)

10.0.0.0/8: Class A (16 million addresses). 172.16.0.0/12: class B (1 million addresses). 192.168.0.0/16: class C (65536 addresses). Loopback: 127.0.0.0/8 (127.0.0.1 = localhost). Link-local: 169.254.0.0/16 (APIPA when no DHCP). NAT: private IP → NAT → public IP. IPv6 private: fc00::/7 (Unique Local Address).

IPv6 – special addresses

::1 = loopback (like 127.0.0.1). ::= undefined (0.0.0.0). ff00::/8 = multicast. fe80::/10 = link-local (automatic configuration). 2001:db8::/32 = documentation/examples. ::ffff:0:0/96 = IPv4-mapped. 64:ff9b::/96 = NAT64 (IPv6→IPv4). 2001::/32 = Teredo (IPv6 tunneling over IPv4). 2002::/16 = 6to4.

FAQ

How does IPv6 solve the IPv4 exhaustion problem?

IPv4: 4.3 billion addresses exhausted (IANA 2011, RIPE NCC 2019). IPv6: 3.4×10³⁸ addresses – practically infinite. Additionally: SLAAC (stateless autoconfiguration) – devices generate addresses themselves. NAT becomes unnecessary. Each device has a globally unique address. Adoption: Poland approx. 50% of IPv6 traffic (2024). Transition: dual-stack (IPv4+IPv6 simultaneously).

How to check your IPv4 and IPv6 address?

Linux/Mac: ip addr show or ifconfig. Windows: ipconfig. Online: ifconfig.me, ipinfo.io, whatismyip.com. Public vs private: ipconfig shows private LAN. The external website will show public. IPv6: ip -6 addr show (Linux). Dual Stack Test: test-ipv6.com. Multiple IPv6 addresses per interface: normally (link-local + global).

How to convert CIDR manually?

192.168.1.0/24: mask = 24 bits = 11111111.11111111.11111111.00000000 = 255.255.255.0. Network address = 192.168.1.0 AND 255.255.255.0 = 192.168.1.0. Broadcast = 192.168.1.0 OR 0.0.0.255 = 192.168.1.255. Hosts = 2^(32-24) - 2 = 256 - 2 = 254. Tools: ipcalc (Linux), online CIDR calc. Python: import ipaddress; ipaddress.ip_network("192.168.1.0/24").

What is subnetting and how to divide the network?

Subnetting: divide a large network into smaller subnets. Example: 192.168.1.0/24 → 4 /26 subnets: .0/26 (hosts .1-.62), .64/26, .128/26, .192/26. Each subnet has 62 hosts instead of 254. Advantages: security (isolation), routing efficiency. VLSM (Variable Length Subnet Masking): different subnet sizes. Rule: each split doubles subnets, splits hosts in half.

How does NAT (Network Address Translation) work?

NAT: The router translates private IP to public. Outgoing: 192.168.1.5:54321 → 85.12.34.56:54321 (public). NAT table: port mapping. SNAT/MASQUERADE: outgoing. DNAT/port forwarding: incoming. CGN (Carrier-Grade NAT): ISP adds another level of NAT. Problem: NAT breaks end-to-end connectivity. IPv6 solves: every device has a global address, NAT is unnecessary.

Related tools: subnet calculator, IP connection tester and WHOIS IP lookup.