More detailsNeighboring subnets, expanded address, reverse DNS, and hextet breakdown
Neighboring /32 subnets
- Expanded address
- Compressed address
- Network (expanded)
- Last address (expanded)
- Prefix mask
- Total addresses (exact)
- Reverse DNS (PTR)
- Host bits / network bits
Hextet breakdown
Quick facts for IPv6 /32
- Prefix mask: ffff:ffff::
- Total addresses: 2⁹⁶
- Approx. count: 7.92 × 10²⁸
- /64 subnets: 2³²
IPv6 /32 reference guideBit split, overview, key facts, sizing tables, design notes, standards, and FAQ
Network / host bit split
- Network bits
- 32
- Host bits
- 96
- Prefix mask
- ffff:ffff::
- Total addresses
- 2⁹⁶
- Approx. count
- 7.92 × 10²⁸
- /64 subnets
- 2³²
- Addresses formula
- 2^96
- /64 relationship
- 2³² × /64 subnets
Overview
A /32 is the standard minimum allocation an ISP receives from an RIR. It contains 2⁹⁶ addresses and can be divided into 65,536 /48 site allocations — or about 4.3 billion /64 LAN subnets. Most internet providers build their entire IPv6 customer base on top of one or more /32s.
Common use cases
- Default ISP allocation from an RIR
- Provider aggregation (one route announced to the internet)
- Suballocating /48s to business customers
Key facts
- A /32 fixes 32 network bits and leaves 96 host bits — 2⁹⁶ total addresses.
- In network design terms, /32 is typically a standard ISP allocation.
- You can subnet a /32 into about 2³² /64 LANs.
- At site scale, /32 equals 2¹⁶ /48 allocations.
Design guidance
A /32 suits organizations that have outgrown a single /48 but do not need a full /32 ISP allocation. Plan your addressing scheme before delegating: assign one /48 (or smaller) per major site, then subnet each site into /64 LANs. Document your nibble boundaries so future growth does not force renumbering.
Practical example
An ISP holding 2001:db8::/32 might announce the entire /32 to upstream providers as one BGP route, then delegate /48 blocks such as 2001:db8:0001::/48 and 2001:db8:0002::/48 to business customers. Each customer subnets their /48 into /64 LANs.
Related RFCs and standards
- RFC 4291IPv6 Addressing Architecture
- RFC 3849IPv6 Documentation Address Prefix (2001:db8::/32)
Prefix sizing reference
Notable /32 networks
2001:db8::/32Documentation / examples (RFC 3849)
Frequently asked questions
Common questions about IPv6 /32 blocks, prefix sizes, and use cases.