Stage 3 → IPv6

IPv6 Subnet Calculator for ISP and MikroTik Networks

Plan IPv6 site and customer segments using prefix length rather than guessing host ranges.

Free to use · Runs locally in your browser · Last reviewed 2026-09-26
Review before deployment: IPv6 has an enormous address space, but operational conventions still matter: customer LANs are commonly /64, sites may receive /56 or /48, and the prefix must be aligned.

Inputs

ipv6-subnets.txt
Change an input to recalculate.
How to use this result
Moving from /48 to /64 creates 2^(64-48) child networks. The calculator prints examples and highlights the address convention; it does not allocate host addresses because SLAAC and privacy addresses are normally chosen by the endpoint.
Do not use the documentation prefix 2001:db8::/32 on a live network. Replace it with the delegated prefix from your provider.
Related tools
VLSM CalculatorPlan IPv4 customer and infrastructure blocks beside IPv6.


Sources and safe-use notes
This page follows the RouterOS documentation and the networking standards linked below. RouterOS syntax, hardware limits, and packet direction depend on your exact release and topology. Export a backup, test one controlled case, and keep a rollback path before applying generated output.
MikroTik documentation · RouterOS manual · RFC 4632 — CIDR · RFC 6598 — shared address space · RFC 8200 — IPv6 · RFC 8200 — IPv6 specification · RFC 4291 — IPv6 addressing architecture