SubnetPad

/18 Subnet Calculator

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A /18 block contains 16,384 addresses with 16,382 usable. A common size for medium-to-large data center segments and cloud VPC subdivision.

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/18 = mask 255.255.192.0 • 16,382 usable addresses

Results for 192.168.0.0/18

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 /18 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 hosts16,384 total addresses in this subnet
More detailsNeighboring subnets, wildcard mask, hex, reverse DNS, and binary breakdown

Neighboring /18 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 address11000000.10101000.00000000.00000000
Subnet mask11111111.11111111.11000000.00000000
Network11000000.10101000.00000000.00000000
Broadcast11000000.10101000.00111111.11111111

Quick facts for /18

/18 reference guideBit split, overview, sizing tables, notable networks, and FAQ

Binary bit split

Network bits (18)Host bits (14)
Network bits
18
Host bits
14
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255
Total addresses
16,384
Usable hosts
16,382
Hosts formula
2^14 − 2
/24 relationship
64 × /24 networks

Overview

A /18 block contains 16,384 addresses with 16,382 usable. A common size for medium-to-large data center segments and cloud VPC subdivision.

Common use cases

  • Cloud VPC subnet allocation
  • Large data center floor or pod
  • University residential network block

Subnet sizing reference

Divide /18 into…

PrefixSubnetsHosts each
/1928,190
/2044,094
/2182,046
/22161,022

/18 fits inside…

SupernetHosts/18s inside
/1732,7662
/1665,5344
/15131,0708
/14262,14216

Frequently asked questions

Common questions about /18 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