CIDR /8Private (RFC 1918)
/8 Subnet Mask (255.0.0.0) - Usable Hosts & CIDR | ipcalc.net
Everything about /8 subnets: Subnet mask 255.0.0.0, wildcard mask 0.255.255.255, 1,67,77,214 usable hosts, binary breakdown, and Cisco configuration templates.
Enter any notation: 192.168.1.1/24, 10.0.0.1 255.255.255.0, or plain IP
Subnet Mask Prefix: /8Netmask: 255.0.0.0
Presets:
32-Bit Subnet Boundary Visualizer
Click any bit position to adjust the CIDR prefix boundary
Network (8 bits)
Host (24 bits)
Octet 110Mask: 255
11111111
Octet 20Mask: 0
00000000
Octet 30Mask: 0
00000000
Octet 40Mask: 0
00000000
Usable Hosts
16,777,214
Total IPs: 16,777,216
Network Address
10.0.0.0
Prefix: /8
Usable Host Range
10.0.0.1
10.255.255.254
Broadcast Address
10.255.255.255
Subnet Broadcast
Detailed Subnet Breakdown
Private (RFC 1918)Subnet Mask
255.0.0.0
Wildcard Mask (Cisco ACL)
0.255.255.255
Hexadecimal IP / Mask
0x0A000000 / 0xFF000000
Integer / Decimal IP
167772160
IP Class & Routing
Class A • Classless Inter-Domain Routing (CIDR)
Reverse DNS (in-addr.arpa)
0.0.0.10.in-addr.arpa
Cisco IOS Command Templates
ip address 10.0.0.0 255.0.0.0
access-list 1 permit 10.0.0.0 0.255.255.255
Technical Subnet Specifications
Prefix Length/8
Dotted Decimal Subnet Mask255.0.0.0
Wildcard Mask (Inverse)0.255.255.255
Total Available IP Addresses1,67,77,216
Usable Host Capacity1,67,77,214 hosts
Network Bits vs Host Bits8 Network / 24 Host
Binary Subnet Mask11111111.00000000.00000000.00000000
Cisco IOS Configuration
Copy-paste templates for Cisco router and switch interface setup:
! Configure Interface
interface GigabitEthernet0/0/1
ip address 10.0.0.1 255.0.0.0
no shutdown
! Access-Control List
access-list 10 permit 10.0.0.0 0.255.255.255
Tip: Wildcard mask is computed by inverting the subnet mask (
~mask).Typical Network Use Cases for /8
A /8 network block provides 1,67,77,216 total IP addresses with 1,67,77,214 usable host interfaces.
Designated Role: Class A Major Network (16M usable).
Frequently Asked Questions: /8 (255.0.0.0)
Authoritative answers to common /8 subnetting, host capacity, and networking questions.
Q1How many usable hosts are in a /8 subnet?
A /8 subnet provides 1,67,77,214 usable host IP addresses out of 1,67,77,216 total addresses. In IPv4 networking, 2 addresses are reserved: the network address (10.0.0.0) and the directed broadcast address (10.255.255.255). Formula: 2^(32 - 8) - 2 = 1,67,77,214 usable hosts.
Q2What is the subnet mask and wildcard mask for /8?
The dotted-decimal subnet mask for a /8 prefix is 255.0.0.0. The corresponding wildcard mask (used in Cisco ACLs and OSPF network statements) is 0.255.255.255. In binary, the subnet mask consists of 8 network bits (1s) followed by 24 host bits (0s).
Q3What are the network, broadcast, and usable IP ranges for 10.0.0.0/8?
For the 10.0.0.0/8 subnet: the Network Address is 10.0.0.0, the Broadcast Address is 10.255.255.255, and the usable host range extends from 10.0.0.1 through 10.255.255.254. Any host interface configured in this subnet must have an IP within this range and netmask 255.0.0.0.
Q4What is a /8 subnet typically used for in network design?
A /8 subnet is typically deployed for class a major network (16m usable). In enterprise and cloud environments (such as AWS VPCs or Azure VNets), /8 allocations provide the optimal balance between host capacity and address conservation.
Q5What does /8 mean in CIDR notation?
Classless Inter-Domain Routing (CIDR) notation expresses the subnet mask as a forward slash followed by the prefix length. A /8 prefix indicates that the first 8 bits of the 32-bit IPv4 address are locked for network identification, leaving the remaining 24 bits available for addressing host interfaces.