This VLSM (Variable Length Subnet Mask) calculator takes a base network (IP + CIDR/mask)
and splits it into multiple sub-nets of just the right size, based on the number of hosts you
need in each one.
How to use:
Enter your Base Network IP (e.g. 10.200.0.0) and its
CIDR or subnet mask (e.g. /16).
Under “Subnets,” for each line give it an optional label and the number of hosts
required (minimum 1).
Click + Add Subnet to add more entries or the “–” button to remove one.
Hit Calculate to generate each subnet’s network address, CIDR,
subnet mask, first/last host, broadcast, and usable host count.
When you’re happy, use Export CSV to download the full table.