IPRangeExplorer

128.0.0.0/3

Public

Class B — /3 prefix — 536,870,910 usable hosts

Network Address
128.0.0.0
Broadcast Address
159.255.255.255
Subnet Mask
224.0.0.0
Usable Hosts
536,870,910
First Usable IP
128.0.0.1
Last Usable IP
159.255.255.254
Total IPs
536,870,912
Prefix Length
/3

Network address — the base address of the block (128.0.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 159.255.255.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 536,870,910 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask — 224.0.0.0 is the dotted-decimal equivalent of /3. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 128.0.0.0/3
Network Address 128.0.0.0
Broadcast Address 159.255.255.255
Subnet Mask 224.0.0.0
Wildcard Mask 31.255.255.255
Prefix Length /3
IP Address Class Class B
Total IP Addresses 536,870,912
Usable Host Addresses 536,870,910
First Usable IP 128.0.0.1
Last Usable IP 159.255.255.254
Network (Hex) 0x80000000
Broadcast (Hex) 0x9FFFFFFF
Address Type Public / Globally Routable

Binary Representation

Network Address
10 10000000.00000000.00000000.00000000
Subnet Mask
11100000.00000000.00000000.00000000

The first 3 bits (1s in the mask) identify the network. The remaining 29 bits identify hosts within the network.

Split into Equal Subnets

Split 128.0.0.0/3 into 2 equal /4 subnets (268,435,454 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 128.0.0.0/4 128.0.0.0 128.0.0.1 143.255.255.254 143.255.255.255 268,435,454
2 144.0.0.0/4 144.0.0.0 144.0.0.1 159.255.255.254 159.255.255.255 268,435,454

/3 Subnet Reference

Total IPs 536,870,912
Usable Hosts 536,870,910
Subnet Mask 224.0.0.0
Wildcard 31.255.255.255
Full /3 reference →

Related Ranges

Parent /2 block 128.0.0.0/2 Sibling /3 block 160.0.0.0/3

Adjacent Prefix Sizes

/1 2,147,483,646 hosts /2 1,073,741,822 hosts /3 536,870,910 hosts /4 268,435,454 hosts /5 134,217,726 hosts

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