IPv6 CIDR to Range
Calculate an IPv6 network’s boundaries.
An IPv6 CIDR prefix such as 2001:db8::/32 describes a block of addresses. This converts the prefix into its first address, last address and total count — what you need when writing firewall rules or planning allocations.
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How IPv6 CIDR to Range works
What it does
Calculate an IPv6 network’s boundaries.
What you get
The first address, last address and size of the IPv6 block.
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What if a check cannot finish?
Confirm your input and try again. A timeout, blocked request, or unavailable provider is not proof that a domain is broken. Internet measurements and third-party services have limits.
IPv6 CIDR to Range — frequently asked questions
What does the /32 mean?
The number of leading bits fixed by the prefix. A /32 fixes the first 32 bits and leaves 96 free, so the block holds 2^96 addresses.
Why are IPv6 blocks so large?
The address space is 128 bits, so allocations are sized for easy subnetting rather than scarcity. A /64 per subnet is the norm even for two hosts.
Is the first address reserved like IPv4's network address?
IPv6 has no broadcast address, but the all-zeros host address is reserved as the subnet-router anycast address. In practice you do not assign it to a host.