/20 Subnet
Subnet Mask
255.255.240.0
Wildcard Mask
0.0.15.255
Total IPs
4,096
Usable Hosts
4,094
Network Bits
20
Host Bits
12
About /20 Networks
Large subnet — small data center or department (4,094 hosts). A /20 subnet uses the mask 255.255.240.0 and provides 4,094 usable host addresses out of 4,096 total IPs.
Example /20 Networks
| Network | Broadcast | First Host | Last Host |
|---|---|---|---|
| 10.0.0.0/20 | 10.0.15.255 | 10.0.0.1 | 10.0.15.254 |
| 172.16.0.0/20 | 172.16.15.255 | 172.16.0.1 | 172.16.15.254 |
| 192.168.0.0/20 | 192.168.15.255 | 192.168.0.1 | 192.168.15.254 |
| 192.168.0.0/20 | 192.168.15.255 | 192.168.0.1 | 192.168.15.254 |
| 8.8.0.0/20 | 8.8.15.255 | 8.8.0.1 | 8.8.15.254 |
Adjacent CIDRs
Frequently Asked Questions
What is a /20 subnet?
A /20 subnet uses the subnet mask 255.255.240.0 with 4,094 usable host addresses and 4,096 total IP addresses. It has 20 network bits and 12 host bits.
How many hosts in a /20 network?
A /20 network supports 4,094 usable hosts out of 4,096 total IP addresses. The usable range excludes the network address and broadcast address.
What subnet mask does /20 use?
A /20 subnet uses the mask 255.255.240.0 (wildcard mask 0.0.15.255). This means the first 20 bits identify the network and the remaining 12 bits identify hosts.