How Many IPs in a /28?
16 addresses, 14 usable, mask 255.255.255.240.
A /28 is the smallest subnet AWS allows in a VPC, and with 16 addresses the reserved ones matter.
| Subnet mask | 255.255.255.240 |
|---|---|
| Wildcard mask | 0.0.0.15 |
| Total addresses | 16 |
| Usable hosts | 14 |
| In /24 terms | 16 of them fit in one /24. |
| Example (10.0.0.0/28) | 10.0.0.0 - 10.0.0.15 |
Usable addresses in cloud subnets
Cloud providers reserve extra addresses in every subnet, so fewer than 14 are available to your machines.
| AWS | 11 usable |
|---|---|
| Azure | 11 usable |
| Google Cloud | 12 usable |
| Oracle Cloud | 13 usable |
Limits and reserved counts are commonly documented values; check your provider's current documentation before you plan around them.
Other sizes
/22 | /23 | /25 | /26 | /27 | /28
Split a block into /28 subnets with the subnet splitter, or calculate any block with the CIDR calculator.
FAQ
How many usable IP addresses are in a /28?
14 usable addresses out of 16. The network and broadcast addresses are reserved.
What is the subnet mask for /28?
255.255.255.240, with wildcard mask 0.0.0.15.
How many usable addresses does a /28 have in AWS?
11, because AWS reserves five addresses in every subnet.