/28 vs /32 — Subnet Comparison
A /28 subnet is 16× larger than a /32. Every additional bit in the prefix halves the address space — the 4-bit difference between these two means /28 has 24 = 16 times as many addresses.
14 usable hosts — tiny segment
Typical Uses
- →AWS VPC endpoint subnet
- →NAT gateway dedicated subnet
- →Small server cluster
Single host address
Typical Uses
- →Host route in routing table
- →Loopback interface address
- →Security group rule for a single IP
Key Differences
How 16 /32 Subnets Divide a /28
Example using 10.0.0.0/28 as the parent block.
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 10.0.0.0/32 | 10.0.0.0 | 10.0.0.0 | 10.0.0.0 | 10.0.0.0 | 1 |
| 2 | 10.0.0.1/32 | 10.0.0.1 | 10.0.0.1 | 10.0.0.1 | 10.0.0.1 | 1 |
| 3 | 10.0.0.2/32 | 10.0.0.2 | 10.0.0.2 | 10.0.0.2 | 10.0.0.2 | 1 |
| 4 | 10.0.0.3/32 | 10.0.0.3 | 10.0.0.3 | 10.0.0.3 | 10.0.0.3 | 1 |
| 5 | 10.0.0.4/32 | 10.0.0.4 | 10.0.0.4 | 10.0.0.4 | 10.0.0.4 | 1 |
| 6 | 10.0.0.5/32 | 10.0.0.5 | 10.0.0.5 | 10.0.0.5 | 10.0.0.5 | 1 |
| 7 | 10.0.0.6/32 | 10.0.0.6 | 10.0.0.6 | 10.0.0.6 | 10.0.0.6 | 1 |
| 8 | 10.0.0.7/32 | 10.0.0.7 | 10.0.0.7 | 10.0.0.7 | 10.0.0.7 | 1 |
| 9 | 10.0.0.8/32 | 10.0.0.8 | 10.0.0.8 | 10.0.0.8 | 10.0.0.8 | 1 |
| 10 | 10.0.0.9/32 | 10.0.0.9 | 10.0.0.9 | 10.0.0.9 | 10.0.0.9 | 1 |
| 11 | 10.0.0.10/32 | 10.0.0.10 | 10.0.0.10 | 10.0.0.10 | 10.0.0.10 | 1 |
| 12 | 10.0.0.11/32 | 10.0.0.11 | 10.0.0.11 | 10.0.0.11 | 10.0.0.11 | 1 |
| 13 | 10.0.0.12/32 | 10.0.0.12 | 10.0.0.12 | 10.0.0.12 | 10.0.0.12 | 1 |
| 14 | 10.0.0.13/32 | 10.0.0.13 | 10.0.0.13 | 10.0.0.13 | 10.0.0.13 | 1 |
| 15 | 10.0.0.14/32 | 10.0.0.14 | 10.0.0.14 | 10.0.0.14 | 10.0.0.14 | 1 |
| 16 | 10.0.0.15/32 | 10.0.0.15 | 10.0.0.15 | 10.0.0.15 | 10.0.0.15 | 1 |
FAQ
What is the difference between /28 and /32?
A /28 has 14 usable hosts
and a /32 has 1.
The subnet masks differ: /28 uses 255.255.255.240
while /32 uses 255.255.255.255.
Every additional bit in the prefix halves the number of addresses — so the 4-bit gap means
/28 is exactly 16× larger.
How many /32 subnets fit in a /28?
Exactly 16 /32 subnets fit perfectly inside one /28 with no wasted space. To split a /28 into /32s, just increment the last 4 bits of the network address for each new subnet.
Which should I choose?
/28 is typically used for: AWS NAT/endpoint dedicated subnet. /32 is better for: Single host — firewall rules, host routes. Choose the smallest prefix that comfortably fits your host count — over-allocating wastes address space, but under-allocating means painful renumbering later.