Guide
IPv4 vs IPv6
IPv4 and IPv6 are two versions of Internet Protocol addressing. They solve the same routing problem with different address sizes and notation.
Last reviewed: June 12, 2026
Calculate an IPv4 or IPv6 network
Quick reference
Quick comparison
- IPv4
- 32-bit addresses written as dotted decimal, such as 8.8.8.8.
- IPv6
- 128-bit addresses written as hexadecimal groups, such as 2001:db8::1.
- Dual stack
- A network or device can support both address families at the same time.
- CIDR
- Both IPv4 and IPv6 networks use slash prefix notation, such as /24 or /64.
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Guide
IPv4
IPv4 addresses are 32-bit addresses commonly written as four decimal numbers separated by dots.
Because IPv4 space is limited, most networks use NAT, proxies, or shared gateway addresses to let many devices use fewer public addresses.
Guide
IPv6
IPv6 addresses are 128-bit addresses written in hexadecimal groups separated by colons.
IPv6 has a much larger address space and commonly uses prefix lengths such as /64, /48, or /32 to describe networks.
Reference
Key terms
- IPv4 size
- 32 bits
- IPv6 size
- 128 bits
- Dual stack
- A network or host that supports IPv4 and IPv6
Examples
Examples
IPv4
87.61.86.92
Dotted decimal notation.
Look up the IPv4 example
IPv6
2001:db8::1
Colon-separated hexadecimal notation.
Calculate the IPv6 example
Next steps
Related guides and tools
Questions
FAQ
Is IPv6 always better than IPv4?
Not always for a single request. IPv6 has more address space, but routing, ISP support, firewalls, and application support still matter.
Can the same user have both IPv4 and IPv6?
Yes. Many networks are dual stack, so the same browser may use IPv4 for one service and IPv6 for another.
Sources