IPv6 subnet calculator
Enter an IPv6 address and prefix. See the full and compressed forms, the prefix's first and last address, how many /64 networks it holds, and split it into smaller prefixes.
| Compressed | 2001:db8:abcd:12::1 |
|---|---|
| Expanded | 2001:0db8:abcd:0012:0000:0000:0000:0001 |
| Prefix | 2001:db8:abcd::/56 |
| First address | 2001:0db8:abcd:0000:0000:0000:0000:0000 |
| Last address | 2001:0db8:abcd:00ff:ffff:ffff:ffff:ffff |
| Addresses | 272 = ≈ 4.722 × 10^21 |
| /64 networks | 256 |
| Scope | Documentation (2001:db8::/32) |
| Reverse zone | 0.0.d.c.b.a.8.b.d.0.1.0.0.2.ip6.arpa |
Split 2001:db8:abcd::/56
| # | Prefix |
|---|---|
| 1 | 2001:db8:abcd::/64 |
| 2 | 2001:db8:abcd:1::/64 |
| 3 | 2001:db8:abcd:2::/64 |
| 4 | 2001:db8:abcd:3::/64 |
| 5 | 2001:db8:abcd:4::/64 |
| 6 | 2001:db8:abcd:5::/64 |
| 7 | 2001:db8:abcd:6::/64 |
| 8 | 2001:db8:abcd:7::/64 |
| 9 | 2001:db8:abcd:8::/64 |
| 10 | 2001:db8:abcd:9::/64 |
| 11 | 2001:db8:abcd:a::/64 |
| 12 | 2001:db8:abcd:b::/64 |
| 13 | 2001:db8:abcd:c::/64 |
| 14 | 2001:db8:abcd:d::/64 |
| 15 | 2001:db8:abcd:e::/64 |
| 16 | 2001:db8:abcd:f::/64 |
| 17 | 2001:db8:abcd:10::/64 |
| 18 | 2001:db8:abcd:11::/64 |
| 19 | 2001:db8:abcd:12::/64 |
| 20 | 2001:db8:abcd:13::/64 |
| 21 | 2001:db8:abcd:14::/64 |
| 22 | 2001:db8:abcd:15::/64 |
| 23 | 2001:db8:abcd:16::/64 |
| 24 | 2001:db8:abcd:17::/64 |
| 25 | 2001:db8:abcd:18::/64 |
| 26 | 2001:db8:abcd:19::/64 |
| 27 | 2001:db8:abcd:1a::/64 |
| 28 | 2001:db8:abcd:1b::/64 |
| 29 | 2001:db8:abcd:1c::/64 |
| 30 | 2001:db8:abcd:1d::/64 |
| 31 | 2001:db8:abcd:1e::/64 |
| 32 | 2001:db8:abcd:1f::/64 |
| 33 | 2001:db8:abcd:20::/64 |
| 34 | 2001:db8:abcd:21::/64 |
| 35 | 2001:db8:abcd:22::/64 |
| 36 | 2001:db8:abcd:23::/64 |
| 37 | 2001:db8:abcd:24::/64 |
| 38 | 2001:db8:abcd:25::/64 |
| 39 | 2001:db8:abcd:26::/64 |
| 40 | 2001:db8:abcd:27::/64 |
| 41 | 2001:db8:abcd:28::/64 |
| 42 | 2001:db8:abcd:29::/64 |
| 43 | 2001:db8:abcd:2a::/64 |
| 44 | 2001:db8:abcd:2b::/64 |
| 45 | 2001:db8:abcd:2c::/64 |
| 46 | 2001:db8:abcd:2d::/64 |
| 47 | 2001:db8:abcd:2e::/64 |
| 48 | 2001:db8:abcd:2f::/64 |
| 49 | 2001:db8:abcd:30::/64 |
| 50 | 2001:db8:abcd:31::/64 |
| 51 | 2001:db8:abcd:32::/64 |
| 52 | 2001:db8:abcd:33::/64 |
| 53 | 2001:db8:abcd:34::/64 |
| 54 | 2001:db8:abcd:35::/64 |
| 55 | 2001:db8:abcd:36::/64 |
| 56 | 2001:db8:abcd:37::/64 |
| 57 | 2001:db8:abcd:38::/64 |
| 58 | 2001:db8:abcd:39::/64 |
| 59 | 2001:db8:abcd:3a::/64 |
| 60 | 2001:db8:abcd:3b::/64 |
| 61 | 2001:db8:abcd:3c::/64 |
| 62 | 2001:db8:abcd:3d::/64 |
| 63 | 2001:db8:abcd:3e::/64 |
| 64 | 2001:db8:abcd:3f::/64 |
Showing the first 64.
How IPv6 addresses are laid out
A typical global unicast address splits cleanly on 16-bit boundaries: the first 48 bits are the global routing prefix your ISP or RIR assigns, the next 16 are your subnet ID (65,536 possible LANs per /48), and the last 64 are the interface ID. Because prefixes usually fall on a nibble (4-bit) boundary, you can often subnet just by editing hex digits: 2001:db8:abcd:0012::/64 is LAN number 0x12 of the /48.
Converting an IPv4 address into IPv6 notation? See IPv4 to IPv6. For IPv4 subnets, use the subnet calculator.
Questions people ask
Why is every IPv6 LAN a /64?
SLAAC (stateless address autoconfiguration, RFC 4862) builds the host part from 64 bits, and many features assume it. RFC 7421 explains the consequences of smaller subnets. Use /64 for every LAN segment, even tiny ones; use /127 only for point-to-point router links.
How big a prefix will I get from my ISP?
RIPE-690 and similar guidance recommend a /48 per business site and a /56 for home users, though some ISPs give only a /64. A /56 contains 256 /64 networks; a /48 contains 65,536.
How do I shorten an IPv6 address?
Drop leading zeros in each group, then replace the single longest run of all-zero groups with
:: (RFC 5952). 2001:0db8:0000:0000:0000:ff00:0042:8329 becomes 2001:db8::ff00:42:8329.Is there a broadcast address in IPv6?
No. IPv6 has no broadcast; it uses multicast (for example ff02::1 for all nodes on a link). All addresses in a prefix are usable, though the all-zeros one is reserved as the subnet-router anycast address.