/1 vs /5 — Subnet Comparison
A /1 subnet is 16× larger than a /5. Every additional bit in the prefix halves the address space — the 4-bit difference between these two means /1 has 24 = 16 times as many addresses.
Key Differences
How 16 /5 Subnets Divide a /1
Example using 10.0.0.0/1 as the parent block.
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 0.0.0.0/5 | 0.0.0.0 | 0.0.0.1 | 7.255.255.254 | 7.255.255.255 | 134,217,726 |
| 2 | 8.0.0.0/5 | 8.0.0.0 | 8.0.0.1 | 15.255.255.254 | 15.255.255.255 | 134,217,726 |
| 3 | 16.0.0.0/5 | 16.0.0.0 | 16.0.0.1 | 23.255.255.254 | 23.255.255.255 | 134,217,726 |
| 4 | 24.0.0.0/5 | 24.0.0.0 | 24.0.0.1 | 31.255.255.254 | 31.255.255.255 | 134,217,726 |
| 5 | 32.0.0.0/5 | 32.0.0.0 | 32.0.0.1 | 39.255.255.254 | 39.255.255.255 | 134,217,726 |
| 6 | 40.0.0.0/5 | 40.0.0.0 | 40.0.0.1 | 47.255.255.254 | 47.255.255.255 | 134,217,726 |
| 7 | 48.0.0.0/5 | 48.0.0.0 | 48.0.0.1 | 55.255.255.254 | 55.255.255.255 | 134,217,726 |
| 8 | 56.0.0.0/5 | 56.0.0.0 | 56.0.0.1 | 63.255.255.254 | 63.255.255.255 | 134,217,726 |
| 9 | 64.0.0.0/5 | 64.0.0.0 | 64.0.0.1 | 71.255.255.254 | 71.255.255.255 | 134,217,726 |
| 10 | 72.0.0.0/5 | 72.0.0.0 | 72.0.0.1 | 79.255.255.254 | 79.255.255.255 | 134,217,726 |
| 11 | 80.0.0.0/5 | 80.0.0.0 | 80.0.0.1 | 87.255.255.254 | 87.255.255.255 | 134,217,726 |
| 12 | 88.0.0.0/5 | 88.0.0.0 | 88.0.0.1 | 95.255.255.254 | 95.255.255.255 | 134,217,726 |
| 13 | 96.0.0.0/5 | 96.0.0.0 | 96.0.0.1 | 103.255.255.254 | 103.255.255.255 | 134,217,726 |
| 14 | 104.0.0.0/5 | 104.0.0.0 | 104.0.0.1 | 111.255.255.254 | 111.255.255.255 | 134,217,726 |
| 15 | 112.0.0.0/5 | 112.0.0.0 | 112.0.0.1 | 119.255.255.254 | 119.255.255.255 | 134,217,726 |
| 16 | 120.0.0.0/5 | 120.0.0.0 | 120.0.0.1 | 127.255.255.254 | 127.255.255.255 | 134,217,726 |
FAQ
What is the difference between /1 and /5?
A /1 has 2,147,483,646 usable hosts
and a /5 has 134,217,726.
The subnet masks differ: /1 uses 128.0.0.0
while /5 uses 248.0.0.0.
Every additional bit in the prefix halves the number of addresses — so the 4-bit gap means
/1 is exactly 16× larger.
How many /5 subnets fit in a /1?
Exactly 16 /5 subnets fit perfectly inside one /1 with no wasted space. To split a /1 into /5s, just increment the last 4 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.