Subnet Expert

CIDR /9 Subnet Reference

Detailed information about IPv4 /9 subnets

/9 Subnet Details

A /9 network is very large and can support thousands to millions of hosts. These are typically used by large organizations or internet service providers.

Key Information

CIDR Notation/9
Subnet Mask255.128.0.0
Binary Subnet Mask11111111 10000000 00000000 00000000

Host Information

Total Addresses8,388,608
Usable Hosts (Standard)8,388,606
AWS Usable IPs8,388,601
Azure Usable IPs8,388,601
GCP Usable IPs8,388,602

Using /9 in Networks

A CIDR /9 subnet has 8,388,606 usable IP addresses for hosts. This is a relatively large subnet that can be further divided into smaller subnets if needed.

Organizations typically use subnets of this size for large-scale deployments or when planning for future growth.

Cloud Provider Considerations

Cloud providers reserve some IP addresses in each subnet for internal use, resulting in fewer usable IPs:

  • AWS: 8,388,601 usable IPs(reserves 5 IPs per subnet)
  • Azure: 8,388,601 usable IPs(reserves 5 IPs per subnet)
  • GCP: 8,388,602 usable IPs(reserves 4 IPs per subnet)

When planning your cloud infrastructure, consider these reserved addresses to accurately size your subnets.

Subnet Calculator

Use our interactive subnet calculator to visualize and manipulate subnets with ease.

Go to Subnet Calculator

Other CIDR References

/0/1/2/3/4/5/6/7/8/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32
← Back to Subnet Calculator