/20 subnet
Mask 255.255.240.0 · 4,094 usable hosts · 4,096 addresses
| Subnet mask | 255.255.240.0 |
|---|---|
| Wildcard mask | 0.0.15.255 |
| Binary mask | 11111111.11111111.11110000.00000000 |
| Network / host bits | 20 / 12 |
| Total addresses | 4,096 |
| Usable hosts | 4,094 |
| Per /8 · /16 · /24 | 4,096 · 16 · – |
| Example | 192.168.10.77/20 → network 192.168.0.0, hosts 192.168.0.1 – 192.168.15.254, broadcast 192.168.15.255 |
Where /20 is used
Default VPC subnet size in AWS default VPCs is /20.
Block boundaries: a /20 must start at a multiple of 4,096 addresses. Calculate any specific address in the subnet calculator.
Neighbouring prefixes
Questions
How many hosts in a /20?
4,096 addresses, of which 4,094 are usable (the first is the network address and the last is broadcast).
What is the subnet mask for /20?
255.255.240.0. In binary: 11111111.11111111.11110000.00000000. The wildcard (inverse) mask is 0.0.15.255.