/25 vs /26 — Subnet Comparison
A /25 subnet is 2× larger than a /26. Every additional bit in the prefix halves the address space — the 1-bit difference between these two means /25 has 21 = 2 times as many addresses.
126 usable hosts — half a /24
Typical Uses
- →Public vs private half of a /24
- →Department sub-segment
- →Smaller cloud application subnets
62 usable hosts — quarter of a /24
Typical Uses
- →Cloud subnet per tier (web, app, db)
- →Small department or team VLAN
- →Security zone isolation
Key Differences
How 2 /26 Subnets Divide a /25
Example using 10.0.0.0/25 as the parent block.
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 10.0.0.0/26 | 10.0.0.0 | 10.0.0.1 | 10.0.0.62 | 10.0.0.63 | 62 |
| 2 | 10.0.0.64/26 | 10.0.0.64 | 10.0.0.65 | 10.0.0.126 | 10.0.0.127 | 62 |
FAQ
What is the difference between /25 and /26?
A /25 has 126 usable hosts
and a /26 has 62.
The subnet masks differ: /25 uses 255.255.255.128
while /26 uses 255.255.255.192.
Every additional bit in the prefix halves the number of addresses — so the 1-bit gap means
/25 is exactly 2× larger.
How many /26 subnets fit in a /25?
Exactly 2 /26 subnets fit perfectly inside one /25 with no wasted space. To split a /25 into /26s, just increment the last 1 bit of the network address for each new subnet.
Which should I choose?
/25 is typically used for: Half a /24 — public/private split. /26 is better for: Cloud per-tier subnet, small VLAN. Choose the smallest prefix that comfortably fits your host count — over-allocating wastes address space, but under-allocating means painful renumbering later.