IPv6 calculator

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

What it is for

Paste a list of assigned prefixes and find overlaps.

Why it helps

Catch double-booking (e.g. ::0/127 and ::1/128 in the same pool) before deploy or BGP announce.

Overlap check

Result

Paste a prefix list. Overlapping pairs appear below.