VLAN Planner

Plan VLAN subnets with VLSM allocation. Add departments with host counts and get optimized IP ranges.

Root Network

Base IP address of your network.

Departments

Engineering120 hosts · VLAN 10
HR25 hosts · VLAN 20
Guest WiFi50 hosts · VLAN 30
VLSM Allocation
3
Departments
224
IPs Used
65,536
Total Capacity
0.3%
Used

Allocation Table

DepartmentVLANNeededUsableNetworkRangeBroadcastMask
Engineering1012012610.0.0.010.0.0.110.0.0.12610.0.0.127/25
Guest WiFi30506210.0.0.12810.0.0.12910.0.0.19010.0.0.191/26
HR20253010.0.0.19210.0.0.19310.0.0.22210.0.0.223/27
Documentation

How It Works

The VLAN Planner uses VLSM (Variable Length Subnet Mask) to efficiently allocate IP blocks. It sorts departments by size (largest first) and assigns the smallest power-of-2 block that fits each department's host count plus network/broadcast overhead.

VLSM Algorithm

Step 1: Sort departments by host count (largest first)
Step 2: Calculate smallest /xx that fits hosts + 2
Step 3: Align to block boundary, assign IPs
Step 4: Repeat for each department sequentially

Last Updated: February 2026. IPv4 only.

Frequently Asked Questions
How to Use

About the VLAN Planner

What it calculates

This vlan planner helps with subnetting, bandwidth, DNS TTL, and other IT networking calculations. Plan VLAN subnets with VLSM allocation for departments and segments.

When to use it

Use for network planning, certification prep, and sysadmin troubleshooting.

Example

Adjust the inputs above to model your specific scenario with the VLAN Planner.

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