CIDR /16 Subnet Reference

A large IPv4 subnet with 65.536 total addresses and 65.534 usable host addresses.

Subnet Mask255.255.0.0
Wildcard Mask0.0.255.255
Total IPs65.536
Usable Hosts65.534
Mask (Hex)FFFF0000
Host Bits16

Binary Breakdown

Subnet Mask11111111.11111111.00000000.00000000
Wildcard Mask00000000.00000000.11111111.11111111

Network bits (1s): 16 ·  Host bits (0s): 16

Common Uses for /16

  • Class B network (legacy)
  • Corporate LANs
  • AWS default VPC (/16 is AWS best practice)
  • 65,534 usable hosts

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Enter any IP address with /16 prefix to calculate exact network details.

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Frequently Asked Questions

What is the subnet mask for /16?

The subnet mask for /16 is 255.255.0.0 (hex: FFFF0000). In binary: 11111111.11111111.00000000.00000000.

How many hosts does a /16 subnet support?

A /16 subnet has 65.536 total addresses. Subtract 2 (network + broadcast) = 65.534 usable host addresses.

What is the wildcard mask for /16?

The wildcard mask (inverse mask) for /16 is 0.0.255.255. Used in Cisco ACLs and OSPF configurations to match the host portion of an address.

What is CIDR /16 used for?

Class B network (legacy). Corporate LANs. AWS default VPC (/16 is AWS best practice). 65,534 usable hosts.

Complete CIDR Reference Table /0–/32

PrefixSubnet MaskWildcardTotal IPsUsable Hosts
/00.0.0.0255.255.255.2554.294.967.2964.294.967.294
/1128.0.0.0127.255.255.2552.147.483.6482.147.483.646
/2192.0.0.063.255.255.2551.073.741.8241.073.741.822
/3224.0.0.031.255.255.255536.870.912536.870.910
/4240.0.0.015.255.255.255268.435.456268.435.454
/5248.0.0.07.255.255.255134.217.728134.217.726
/6252.0.0.03.255.255.25567.108.86467.108.862
/7254.0.0.01.255.255.25533.554.43233.554.430
/8255.0.0.00.255.255.25516.777.21616.777.214
/9255.128.0.00.127.255.2558.388.6088.388.606
/10255.192.0.00.63.255.2554.194.3044.194.302
/11255.224.0.00.31.255.2552.097.1522.097.150
/12255.240.0.00.15.255.2551.048.5761.048.574
/13255.248.0.00.7.255.255524.288524.286
/14255.252.0.00.3.255.255262.144262.142
/15255.254.0.00.1.255.255131.072131.070
/16255.255.0.00.0.255.25565.53665.534
/17255.255.128.00.0.127.25532.76832.766
/18255.255.192.00.0.63.25516.38416.382
/19255.255.224.00.0.31.2558.1928.190
/20255.255.240.00.0.15.2554.0964.094
/21255.255.248.00.0.7.2552.0482.046
/22255.255.252.00.0.3.2551.0241.022
/23255.255.254.00.0.1.255512510
/24255.255.255.00.0.0.255256254
/25255.255.255.1280.0.0.127128126
/26255.255.255.1920.0.0.636462
/27255.255.255.2240.0.0.313230
/28255.255.255.2400.0.0.151614
/29255.255.255.2480.0.0.786
/30255.255.255.2520.0.0.342
/31255.255.255.2540.0.0.122
/32255.255.255.2550.0.0.011