How big is the IPv4 address space?

IPv4 uses 32-bit addresses, so there are 2^32 = 4,294,967,296 possible addresses. This map divides them into 256 blocks of 16,777,216 addresses each, called /8 blocks.

A /8 block is a range where the first 8 bits (the first number) are fixed. For example 10.0.0.0/8 covers every address from 10.0.0.0 to 10.255.255.255 — about 16.7 million addresses.

Why are some blocks private or reserved?

Certain ranges are set aside for special jobs: 10.0.0.0/8 for private networks, 127.0.0.0/8 for loopback, 224.0.0.0/4 for multicast, and 240.0.0.0/4 as reserved. The rest are public unicast addresses delegated to Regional Internet Registries.

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IPv4 Address Space Map

The entire IPv4 internet on one screen. Each square is a /8 block (16,777,216 addresses); all 256 of them make up the ~4.3 billion IPv4 addresses. Hover or tap a block to see what it's used for.

Public unicast Private (RFC 1918) Public w/ special sub-block Loopback Multicast Reserved

Hover a block to see its designation. First block is 0.0.0.0/8, last is 255.0.0.0/8.

What this map shows

IPv4 addresses are 32 bits, giving 2³² = 4,294,967,296 possible addresses. The most natural way to carve that up is into 256 /8 blocks — one for each value of the first number (0–255). Each /8 holds about 16.7 million addresses. This grid draws all 256, coloured by the primary job of that block.

Note

This is a simplified view. Most blocks are public unicast addresses delegated to the Regional Internet Registries (ARIN, RIPE, APNIC, LACNIC, AFRINIC). Several otherwise-public /8s contain smaller special-use sub-blocks (for example 172.16.0.0/12 lives inside 172.0.0.0/8) — those are marked in teal and explained on hover. See the full list in our private & reserved IP ranges reference.

The special blocks

10.0.0.0/8 — private networks (RFC 1918).
127.0.0.0/8 — loopback; 127.0.0.1 is "localhost".
224.0.0.0/4 (224–239) — multicast.
240.0.0.0/4 (240–255) — reserved; 255.255.255.255 is the limited broadcast address.
0.0.0.0/8 — "this network" / unspecified.

Want the theory? Read what an IP address is, how IPv4 ran out of room, and reserved & special IP addresses. To do the maths on a specific block, try the subnet calculator or CIDR → range tools.

Frequently asked questions

How many addresses are in a /8 block?

Each /8 holds 2²⁴ = 16,777,216 addresses (256 × 256 × 256). All 256 /8 blocks together make the full 4,294,967,296 IPv4 addresses.

Why is the whole IPv4 space so small?

32 bits simply can't represent more than ~4.3 billion values. That's why the world ran short of IPv4 addresses and created IPv6, which uses 128-bit addresses.

Is this the same as the RIR allocation map?

Not exactly. Real registry allocations are more granular and change over time. This map focuses on the stable, well-established designations (private, loopback, multicast, reserved) and labels the rest as public unicast.

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