# IPv6 /44 Prefix – 1,048,576 /64 Subnets Explained

> An IPv6 /44 prefix spans 1,048,576 /64 subnets (19,342,813,113,834,066,795,298,816 addresses). Examples, roles and FAQs for planning IPv6 networks.

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# IPv6 /44 Prefix ReferenceIPv6

Sixteen site allocations under one aggregate: a /44 carries 1,048,576 /64 subnets and hands a mid-size organization a /48 for every major location while leaving headroom to spare. It is the working compromise between a lone /48 and a provider-scale /40.

An IPv6 /44 prefix contains 19,342,813,113,834,066,795,298,816 addresses, which splits into 1,048,576 standard /64 subnets.

## /44 facts at a glance

- **Total addresses:** 19,342,813,113,834,066,795,298,816 (284)
- **/64 subnets inside:** 1,048,576
- **Host/interface bits:** 84
- **Example network:** 2001:db8::/44
- **First address:** 2001:db8::
- **Last address:** 2001:db8:f:ffff:ffff:ffff:ffff:ffff
- **Typical role:** Enterprise with many routed sites

## A /44 in documentation space

Using `2001:db8::/32` (RFC 3849 documentation space) aligned to its own boundary, a /44 occupies:

| Block | First address | Last address |
| --- | --- | --- |
| 2001:db8::/44 | 2001:db8:: | 2001:db8:f:ffff:ffff:ffff:ffff:ffff |

## How an IPv6 /44 prefix works

A /44 prefix pins the first 44 bits of a 128-bit address, leaving 84 bits free. That free portion holds 284 = 19,342,813,113,834,066,795,298,816 distinct addresses, and every such block begins at a multiple of that size. Because each subnet should be a /64, the 20 middle bits between the prefix and the /64 boundary give 1,048,576 subnets to hand out.

## Where /44 is used

- Enterprises running up to sixteen sites, each addressed from its own /48.
- Providers delegating beefier blocks to demanding business customers.
- Organizations consolidating scattered /48s into a single routable aggregate.

The split table is tidy: sixteen /48s, four /46s, or 256 /52s — every hop nibble-aligned.

With over a million /64s inside, capacity questions dissolve; routing and delegation hygiene deserve the attention instead.

## Frequently asked questions

**How many addresses does an IPv6 /44 have?**

19,342,813,113,834,066,795,298,816 — 2^84, eighty-four host bits wide.

**How many /48s are in a /44?**

Sixteen. Four bits separate the prefixes, so a /44 is the classic site block multiplied sixteen times over.

**Is a /44 bigger than a /48?**

Yes, by a factor of sixteen. Shorter prefix, bigger block — each bit you shed doubles the space.

**How many /64 subnets can I build from a /44?**

1,048,576 standard subnets, which comfortably covers a multi-building campus with room for decades of growth.

## Open this prefix in the calculator

[Open 2001:db8::/44 in the IPv6 calculator](https://itinsighthub.com/ipv6-subnet-calculator/?q=2001%3Adb8%3A%3A%2F44)

### Related IPv6 prefixes

[/29](https://itinsighthub.com/ipv6/29/)[/32](https://itinsighthub.com/ipv6/32/)[/34](https://itinsighthub.com/ipv6/34/)[/36](https://itinsighthub.com/ipv6/36/)[/40](https://itinsighthub.com/ipv6/40/)[/42](https://itinsighthub.com/ipv6/42/)[/47](https://itinsighthub.com/ipv6/47/)[/48](https://itinsighthub.com/ipv6/48/)[/52](https://itinsighthub.com/ipv6/52/)[/56](https://itinsighthub.com/ipv6/56/)[/60](https://itinsighthub.com/ipv6/60/)[/64](https://itinsighthub.com/ipv6/64/)[/127](https://itinsighthub.com/ipv6/127/)[/128](https://itinsighthub.com/ipv6/128/)

← IPv6 /42 prefix
IPv6 /47 prefix →

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