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/27 Subnet Mask: 255.255.255.224

A /27 prefix fixes the first 27 bits of the address as the network, leaving 5 bits for hosts. That gives 32 addresses, of which 30 can be assigned to hosts.

CIDR notation/27
Subnet mask255.255.255.224
Wildcard mask0.0.0.31
Binary mask11111111.11111111.11111111.11100000
Hex mask0xFFFFFFE0
Total addresses32
Usable hosts30

Example: 192.168.1.0/27

  • Network address: 192.168.1.0
  • First usable host: 192.168.1.1
  • Last usable host: 192.168.1.30
  • Broadcast address: 192.168.1.31

When to use a /27 subnet

Small office networks or VLANs for a single team or device class, often created by splitting a /24 into equal parts.

  • 524,288 /27 subnets fit in a /8.
  • 2,048 /27 subnets fit in a /16.
  • 8 /27 subnets fit in a /24.

Frequently Asked Questions

What is the subnet mask for /27?

The subnet mask for /27 is 255.255.255.224, and its wildcard (inverse) mask is 0.0.0.31.

How many hosts are in a /27?

A /27 contains 32 addresses. Subtracting the network and broadcast addresses leaves 30 usable hosts.