LoginSign Up

/23 Subnet Mask: 255.255.254.0

A /23 prefix fixes the first 23 bits of the address as the network, leaving 9 bits for hosts. That gives 512 addresses, of which 510 can be assigned to hosts.

CIDR notation/23
Subnet mask255.255.254.0
Wildcard mask0.0.1.255
Binary mask11111111.11111111.11111110.00000000
Hex mask0xFFFFFE00
Total addresses512
Usable hosts510

Example: 172.16.0.0/23

  • Network address: 172.16.0.0
  • First usable host: 172.16.0.1
  • Last usable host: 172.16.1.254
  • Broadcast address: 172.16.1.255

When to use a /23 subnet

Larger office or campus segments, and cloud subnets that need hundreds to thousands of addresses.

  • 32,768 /23 subnets fit in a /8.
  • 128 /23 subnets fit in a /16.

Frequently Asked Questions

What is the subnet mask for /23?

The subnet mask for /23 is 255.255.254.0, and its wildcard (inverse) mask is 0.0.1.255.

How many hosts are in a /23?

A /23 contains 512 addresses. Subtracting the network and broadcast addresses leaves 510 usable hosts.