IPv6 Subnet Calculator
Plan IPv6 subnet hierarchies by entering a parent prefix. The calculator breaks down how many child subnets you get at common prefix lengths (/52, /56, /60, /64, /72, etc.) and how many addresses each child subnet contains. Mixed IPv4/IPv6 input is auto-detected — IPv4 addresses are redirected to the IPv4 subnet calculator.
Enter an IPv6 prefix with CIDR (e.g., 2001:db8::/48). Auto-detects IPv4/IPv6.
Common IPv6 Prefix Reference
| Prefix | Typical Use | Subnets from /48 | Addresses per Subnet |
|---|---|---|---|
| /48 | Site allocation (one customer/site) | 1 | 280 |
| /52 | Large campus or multi-building site | 16 | 276 |
| /56 | Medium site / SOHO | 256 | 272 |
| /60 | Small site with multiple VLANs | 4,096 | 268 |
| /64 | Standard LAN subnet (SLAAC) | 65,536 | 264 |