SubnetPad

/16 Subnet Calculator

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A /16 block (historically "Class B") contains 65,536 addresses with 65,534 usable. The 192.168.0.0/16 range is RFC 1918 private space. /16 is the default VPC CIDR in AWS, Azure, and GCP.

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/16 = mask 255.255.0.0 • 65,534 usable addresses

Results for 192.168.0.0/16

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 /16 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 hosts65,536 total addresses in this subnet
More detailsNeighboring subnets, wildcard mask, hex, reverse DNS, and binary breakdown

Neighboring /16 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 mask11111111.11111111.00000000.00000000
Network11000000.10101000.00000000.00000000
Broadcast11000000.10101000.11111111.11111111

Quick facts for /16

/16 reference guideBit split, overview, sizing tables, notable networks, and FAQ

Binary bit split

Network bits (16)Host bits (16)
Network bits
16
Host bits
16
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255
Total addresses
65,536
Usable hosts
65,534
Hosts formula
2^16 − 2
/24 relationship
256 × /24 networks

Overview

A /16 block (historically "Class B") contains 65,536 addresses with 65,534 usable. The 192.168.0.0/16 range is RFC 1918 private space. /16 is the default VPC CIDR in AWS, Azure, and GCP.

Common use cases

  • AWS, Azure, GCP VPC default CIDR block
  • Campus or university networks
  • Large office or data center networks
  • RFC 1918 Class B private space (172.16.0.0–172.31.255.255)

Subnet sizing reference

Divide /16 into…

PrefixSubnetsHosts each
/17232,766
/18416,382
/1988,190
/20164,094

/16 fits inside…

SupernetHosts/16s inside
/15131,0702
/14262,1424
/13524,2868
/121,048,57416

Notable /16 networks

  • 172.16.0.0/16First /16 of RFC 1918 Class B
  • 192.168.0.0/16RFC 1918 Class C range
  • 10.0.0.0/16Common AWS/GCP VPC block

Frequently asked questions

Common questions about /16 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