8 min read
2026-01-28
A subnet calculator helps divide a large network into several smaller segments. This is a fundamental skill for any network professional.
Security — segment isolation limits the spread of threats
Performance — reducing the broadcast domain lowers the load
Management — smaller segments are easier to administer
| CIDR | Mask | Host Count |
|---|---|---|
| /24 | 255.255.255.0 | 254 |
| /25 | 255.255.255.128 | 126 |
| /26 | 255.255.255.192 | 62 |
| /27 | 255.255.255.224 | 30 |
| /28 | 255.255.255.240 | 14 |
| /29 | 255.255.255.248 | 6 |
| /30 | 255.255.255.252 | 2 |
VLSM allows using different masks for subnets within the same network. For example, /28 (14 hosts) for servers, /30 (2 hosts) for point-to-point links.
Enter the source network (e.g., 10.0.0.0/16)
Specify the number of subnets or hosts needed
Get a list of subnets with address ranges
Distribute subnets among segments
Subnet your network with the Subnet Calculator.
See also: IP Calculator, Port List