SubnetPad

/27 Subnet Calculator

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A /27 block contains 32 addresses with 30 usable. Used for small teams, DMZ segments, and cloud subnets that need more than a handful of hosts but don't require a full /26.

/1
/32

/27 = mask 255.255.255.224 • 30 usable addresses

Results for 192.168.1.0/27

Private (RFC 1918)Class C
Network addressThe first address — identifies the subnet itself
Broadcast addressThe last address — used to reach every device at once
Subnet maskSame as /27 in CIDR notation
First usable hostThe first IP you can assign to a device
Last usable hostThe last IP you can assign to a device
Usable hosts32 total addresses in this subnet
More detailsNeighboring subnets, wildcard mask, hex, reverse DNS, and binary breakdown

Neighboring /27 subnets

Wildcard mask
Used in Cisco ACLs and OSPF
CIDR notation
IP in hexadecimal
IP as 32-bit integer
Reverse DNS (PTR)
Host bits / subnet bits

Binary breakdown

IP address11000000.10101000.00000001.00000000
Subnet mask11111111.11111111.11111111.11100000
Network11000000.10101000.00000001.00000000
Broadcast11000000.10101000.00000001.00011111

Quick facts for /27

/27 reference guideBit split, overview, sizing tables, notable networks, and FAQ

Binary bit split

Network bits (27)Host bits (5)
Network bits
27
Host bits
5
Subnet mask
255.255.255.224
Wildcard mask
0.0.0.31
Total addresses
32
Usable hosts
30
Hosts formula
2^5 − 2
/24 relationship
8 fit per /24

Overview

A /27 block contains 32 addresses with 30 usable. Used for small teams, DMZ segments, and cloud subnets that need more than a handful of hosts but don't require a full /26.

Common use cases

  • Small team or floor segment
  • DMZ or perimeter network
  • Cloud load balancer or NAT gateway subnet
  • IoT device segment

Subnet sizing reference

Divide /27 into…

PrefixSubnetsHosts each
/28214
/2946
/3082
/31162

/27 fits inside…

SupernetHosts/27s inside
/26622
/251264
/242548
/2351016

Notable /27 networks

  • 192.168.1.0/27.0–.31
  • 192.168.1.32/27.32–.63
  • 192.168.1.64/27.64–.95

Frequently asked questions

Common questions about /27 networks, subnet masks, and use cases.

All CIDR prefix sizes

/0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32