/11 vs /13 — Subnet Comparison
A /11 subnet is 4× larger than a /13. Every additional bit in the prefix halves the address space — the 2-bit difference between these two means /11 has 22 = 4 times as many addresses.
Key Differences
How 4 /13 Subnets Divide a /11
Example using 10.0.0.0/11 as the parent block.
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 10.0.0.0/13 | 10.0.0.0 | 10.0.0.1 | 10.7.255.254 | 10.7.255.255 | 524,286 |
| 2 | 10.8.0.0/13 | 10.8.0.0 | 10.8.0.1 | 10.15.255.254 | 10.15.255.255 | 524,286 |
| 3 | 10.16.0.0/13 | 10.16.0.0 | 10.16.0.1 | 10.23.255.254 | 10.23.255.255 | 524,286 |
| 4 | 10.24.0.0/13 | 10.24.0.0 | 10.24.0.1 | 10.31.255.254 | 10.31.255.255 | 524,286 |
FAQ
What is the difference between /11 and /13?
A /11 has 2,097,150 usable hosts
and a /13 has 524,286.
The subnet masks differ: /11 uses 255.224.0.0
while /13 uses 255.248.0.0.
Every additional bit in the prefix halves the number of addresses — so the 2-bit gap means
/11 is exactly 4× larger.
How many /13 subnets fit in a /11?
Exactly 4 /13 subnets fit perfectly inside one /11 with no wasted space. To split a /11 into /13s, just increment the last 2 bits of the network address for each new subnet.
Which should I choose?
Choose based on how many hosts you need. Use the hosts → prefix calculator on the homepage to find the right size for your requirements.