IPv4 vs IPv6
IPv4 and IPv6 are both ways of giving every device on the internet an address. IPv4 came first and is still everywhere. IPv6 is the newer system built to fix IPv4's biggest limit: it ran out of addresses.
The core difference
An IPv4 address is 32 bits, written as four numbers like 203.0.113.42. That allows about 4.3 billion addresses, which sounded like plenty in the 1980s and isn't anymore.
An IPv6 address is 128 bits, written in hexadecimal like 2001:db8:85a3::8a2e:370:7334. The pool is so large it's effectively unlimited, enough for every device many times over.
What else changes
- Address supply: IPv4 is exhausted, IPv6 is practically infinite.
- NAT: IPv4 leans on address sharing and translation, IPv6 can give every device its own public address.
- Format: IPv4 uses dotted decimal, IPv6 uses colon-separated hex.
- Adoption: IPv4 still carries most traffic, but IPv6 keeps growing.
Do you need IPv6?
For everyday use you won't notice a difference, and plenty of connections are still IPv4 only. IPv6 is the long-term direction, and turning it on (if your ISP offers it) can help with peer-to-peer apps and sidestep carrier-grade NAT. There's no downside to having both, which is what most modern networks run.