/6 vs /7 — Subnet Comparison
A /6 subnet is 2× larger than a /7. Every additional bit in the prefix halves the address space — the 1-bit difference between these two means /6 has 21 = 2 times as many addresses.
Key Differences
How 2 /7 Subnets Divide a /6
Example using 10.0.0.0/6 as the parent block.
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 8.0.0.0/7 | 8.0.0.0 | 8.0.0.1 | 9.255.255.254 | 9.255.255.255 | 33,554,430 |
| 2 | 10.0.0.0/7 | 10.0.0.0 | 10.0.0.1 | 11.255.255.254 | 11.255.255.255 | 33,554,430 |
FAQ
What is the difference between /6 and /7?
A /6 has 67,108,862 usable hosts
and a /7 has 33,554,430.
The subnet masks differ: /6 uses 252.0.0.0
while /7 uses 254.0.0.0.
Every additional bit in the prefix halves the number of addresses — so the 1-bit gap means
/6 is exactly 2× larger.
How many /7 subnets fit in a /6?
Exactly 2 /7 subnets fit perfectly inside one /6 with no wasted space. To split a /6 into /7s, just increment the last 1 bit 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.