IPv6 calculator

Subnet details, /127 and /128 planning, splitting, compress/expand, overlap check.

What it is for

Divide a larger prefix into equal smaller ones (e.g. /48 → /56 or /64, /64 → /127).

Why it helps

Know the exact subnet count and first rows — allocate your whole /48 without gaps or guessing.

Subnet splitter

E.g. /48 → /64 = 65536 × /64 · /64 → /127 = 2⁶³ pairs.

Quick templates

/48→/64 /48→/56 /64→/127 /64→/128

Split result

From2001:db8:1::/48
To/56
Subnets256
#PrefixNetwork
0 2001:db8:1::/56 2001:db8:1::
1 2001:db8:1:100::/56 2001:db8:1:100::
2 2001:db8:1:200::/56 2001:db8:1:200::
3 2001:db8:1:300::/56 2001:db8:1:300::
4 2001:db8:1:400::/56 2001:db8:1:400::
5 2001:db8:1:500::/56 2001:db8:1:500::
6 2001:db8:1:600::/56 2001:db8:1:600::
7 2001:db8:1:700::/56 2001:db8:1:700::
8 2001:db8:1:800::/56 2001:db8:1:800::
9 2001:db8:1:900::/56 2001:db8:1:900::
10 2001:db8:1:a00::/56 2001:db8:1:a00::
11 2001:db8:1:b00::/56 2001:db8:1:b00::
12 2001:db8:1:c00::/56 2001:db8:1:c00::
13 2001:db8:1:d00::/56 2001:db8:1:d00::
14 2001:db8:1:e00::/56 2001:db8:1:e00::
15 2001:db8:1:f00::/56 2001:db8:1:f00::
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