All tools / Subnet cheat sheet
/12 subnet mask
A /12 block has 1,048,576 addresses with the netmask 255.240.0.0. The size of the private range 172.16.0.0/12.
255.240.0.0| CIDR notation | /12 |
| Netmask | 255.240.0.0 |
| Wildcard mask | 0.15.255.255 |
| Total addresses | 1,048,576 |
| Usable hosts | 1,048,574 |
| Usable in an AWS subnet | n/a (AWS allows /16 to /28) |
| Example range | 10.0.0.0/12: 10.0.0.0 to 10.15.255.255 |
How /12 fits with other sizes
- A /8 holds 16 subnets of /12.
- It splits into 2 subnets of /13.
- It splits into 4 subnets of /14.
- It splits into 16 subnets of /16.