Network

VLSM Planner

Plan variable-length subnet allocations from a base CIDR.

VLSM Planner allocates variable-length subnets from a parent block based on host requirements. It is useful when designing efficient address plans for mixed-size network segments. The tool helps reduce wasted space while keeping subnet boundaries valid. Use it to build a clear addressing scheme before implementation.

VLSM Inputs

Enter base CIDR and required hosts per subnet.

Result

Fits base block: Yes

Used IPs: 240 / 256

Remaining IPs: 16

Subnet	CIDR	Hosts
Subnet 1	10.0.0.0/25	126
Subnet 2	10.0.0.128/26	62
Subnet 3	10.0.0.192/27	30
Subnet 4	10.0.0.224/28	14

How to use this tool

Enter parent CIDR and host counts per required subnet.
Run the planner to generate subnet assignments.
Review allocations and reserve growth room for critical segments.

Subnet design resources

Promote network design labs, CCNA/CCNP prep tools, and IP planning software.

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