SubnetPad

IPv6 /96 Subnet Calculator

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A /96 leaves 32 host bits — the width of an entire IPv4 address. The well-known 64:ff9b::/96 NAT64 prefix and the ::ffff:0:0/96 IPv4-mapped range both use this size to embed IPv4 addresses inside IPv6.

/0
/128

/96 = 2³² addresses (≈ 4.29 × 10⁹)

Results for 2001:db8:abcd:12::/96

Documentation (RFC 3849)Global scope
Network / prefixThe first address — identifies the subnet itself
First addressSubnet-router anycast; first address in the block
Last addressThe highest address in this block
Prefix maskEquivalent to /96
Total addresses≈ 4.29 × 10⁹ addresses
Address typeGlobally routable scope
More detailsNeighboring subnets, expanded address, reverse DNS, and hextet breakdown

Neighboring /96 subnets

Expanded address
Compressed address
Network (expanded)
Last address (expanded)
Prefix mask
Total addresses (exact)
Reverse DNS (PTR)
Host bits / network bits

Hextet breakdown

20010db8abcd00120000000000000001
NetworkSplit groupHost

Quick facts for IPv6 /96

IPv6 /96 reference guideBit split, overview, key facts, sizing tables, design notes, standards, and FAQ

Network / host bit split

Network bits (96)Split hextetHost bits (32)
Network bits
96
Host bits
32
Prefix mask
ffff:ffff:ffff:ffff:ffff:ffff::
Total addresses
2³²
Approx. count
4.29 × 10⁹
/64 subnets
Addresses formula
2^32
/64 relationship
smaller than a /64

Overview

A /96 leaves 32 host bits — the width of an entire IPv4 address. The well-known 64:ff9b::/96 NAT64 prefix and the ::ffff:0:0/96 IPv4-mapped range both use this size to embed IPv4 addresses inside IPv6.

Common use cases

  • NAT64 / IPv4-IPv6 translation (64:ff9b::/96)
  • IPv4-mapped IPv6 addresses (::ffff:0:0/96)

Key facts

  • A /96 fixes 96 network bits and leaves 32 host bits — 2³² total addresses.
  • In network design terms, /96 is typically a specialized sub-/64 block.
  • A /96 is 1/2³² of a standard /64 LAN subnet.

Design guidance

A /96 can work for small management VLANs, out-of-band networks, or certification lab exercises where you deliberately cap the host count. For router interconnects, prefer /127 (RFC 6164) over /96. For ordinary LANs, stay with /64 regardless of how small the segment feels.

Practical example

In a lab, 2001:db8:abcd:0012::1/96 might number a small segment with 2³² addresses. In production, you would normally expand this to a full /64 unless you have a documented exception.

Related RFCs and standards

  • RFC 6052IPv6 Addressing of IPv4/IPv6 Translators (NAT64)

Prefix sizing reference

Divide /96 into…

PrefixSubnetsAddresses each
/9722³¹
/9842³⁰
/100162²⁸
/1042562²⁴

/96 fits inside…

SupernetAddresses/96s inside
/952³³2
/942³⁴4
/922³⁶16
/882⁴⁰256

Notable /96 networks

  • 64:ff9b::/96NAT64 well-known prefix (RFC 6052)
  • ::ffff:0:0/96IPv4-mapped IPv6 addresses

Frequently asked questions

Common questions about IPv6 /96 blocks, prefix sizes, and use cases.