/16 Subnet Mask (255.255.0.0)
| Prefix | /16 |
|---|---|
| Subnet mask | 255.255.0.0 |
| Wildcard mask | 0.0.255.255 |
| Binary mask | 11111111.11111111.00000000.00000000 |
| Total addresses | 65,536 |
| Usable hosts | 65,534 |
| Host bits | 16 |
| Subnets of /16 in a /8 | 256 |
e.g. 10.0.0.5/22 or 10.0.0.5 255.255.252.0
| Network address | 172.16.0.0 | |
|---|---|---|
| Broadcast address | 172.16.255.255 | |
| First usable host | 172.16.0.1 | |
| Last usable host | 172.16.255.254 | |
| Total addresses | 65,536 | |
| Usable hosts | 65,534 | |
| Subnet mask | 255.255.0.0 | |
| Wildcard mask | 0.0.255.255 | |
| CIDR notation | 172.16.0.0/16 | |
| IP class | Class B (legacy) | |
| Address type | Private (RFC 1918) | |
| IP address (binary) | 10101100.00010000.00000000.00000000 | |
| Subnet mask (binary) | 11111111.11111111.00000000.00000000 |
■ network bits ■ host bits
| Requested hosts | CIDR | First host | Last host | Broadcast | Usable hosts |
|---|
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What is a /16 subnet?
A /16 subnet uses the first 16 bits of an IPv4 address for the network and leaves 16 bits for hosts. Its subnet mask is 255.255.0.0, and it contains 2¹⁶ = 65,536 addresses, of which 65,534 can be assigned to devices. Typical use: Former Class B size; common for an entire cloud VPC (AWS default VPC is 172.31.0.0/16) or a campus. Use the subnet calculator above to check any /16 network.
/16 subnet example
For 172.16.0.0/16: network address 172.16.0.0, usable hosts 172.16.0.1 – 172.16.255.254, broadcast address 172.16.255.255, wildcard mask 0.0.255.255.
Frequently asked questions
How many usable IPs are in a /16?
65,534. The block has 65,536 addresses; the first is the network address and the last is the broadcast address.
What is the subnet mask for /16?
255.255.0.0, or 11111111.11111111.00000000.00000000 in binary.
How many /16 subnets are in a /8?
256 (2⁸), because a /16 uses 8 more network bits than a /8.
What is the difference between /16 and /15?
A /15 (255.254.0.0) is twice as large: 131,072 addresses and 131,070 usable hosts, spanning two consecutive /16 blocks such as 172.16.0.0–172.17.255.255.