⚖️ Comparison · Updated for 2026
IPv4 vs IPv6
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
Quick answer: IPv4: 32-bit addresses, ~4.3 billion total — exhausted in 2011. IPv6: 128-bit addresses, 3.4×10³⁸ total — effectively infinite. Most of the internet is dual-stack (supports both) in 2026. IPv6 adoption worldwide is about 50%. ISPs auto-provide both; most users never notice the transition.
Decision guide — when to use which
Use IPv4 when…
Legacy systems, many IoT devices, older networking equipment, private network addressing (192.168.x.x).
Use IPv6 when…
Modern deployments, all new internet infrastructure, mobile networks (5G native IPv6), cloud providers.
📊 Side-by-side comparison
| Aspect | IPv4 | IPv6 |
|---|---|---|
| Address length | 32-bit (4 bytes) | 128-bit (16 bytes) |
| Total addresses | ~4.3 billion | 340 undecillion |
| Example | 192.168.1.1 | 2001:db8::1 |
| Header | Simple, fixed 20 bytes | Extension headers |
| NAT required? | Yes (address exhaustion) | No (abundance) |
Frequently asked
?
Does it matter whether my connection uses IPv4 or IPv6?
For most users, no. Modern operating systems and browsers handle both seamlessly using 'Happy Eyeballs' — they try IPv6 first, fall back to IPv4. IPv6 is slightly faster on some networks because it avoids NAT translation.
?
Will IPv4 stop working?
No — the internet will support both protocols for the foreseeable future. IPv4 addresses are traded commercially and are expensive (roughly $40+ per address in 2026). IPv6 is the long-term direction but IPv4 won't be switched off.
Reviewed for 2026. All conversion factors and historical references verified against official sources (ISO standards, government weights & measures legislation, IEC technical specifications). Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project. We don't sell SEO links or accept paid placements in this content.