How Many IPs in a /27?
32 addresses, 30 usable, mask 255.255.255.224.
A /27 holds enough hosts for a small team or a group of servers, and eight of them fit in a /24.
| Subnet mask | 255.255.255.224 |
|---|---|
| Wildcard mask | 0.0.0.31 |
| Total addresses | 32 |
| Usable hosts | 30 |
| In /24 terms | 8 of them fit in one /24. |
| Example (10.0.0.0/27) | 10.0.0.0 - 10.0.0.31 |
Usable addresses in cloud subnets
Cloud providers reserve extra addresses in every subnet, so fewer than 30 are available to your machines.
| AWS | 27 usable |
|---|---|
| Azure | 27 usable |
| Google Cloud | 28 usable |
| Oracle Cloud | 29 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 /27 subnets with the subnet splitter, or calculate any block with the CIDR calculator.
FAQ
How many usable IP addresses are in a /27?
30 usable addresses out of 32. The network and broadcast addresses are reserved.
What is the subnet mask for /27?
255.255.255.224, with wildcard mask 0.0.0.31.
How many usable addresses does a /27 have in AWS?
27, because AWS reserves five addresses in every subnet.