Subnet planner
Give it a parent range and the segments you need. It sizes each subnet, packs them without overlap and warns you about ranges that tend to clash with home routers, Docker and VPN defaults.
| Segment | Subnet | Usable range | Broadcast | Hosts |
|---|
Why the choice of range matters for tunnels
The day you connect a VPN to your home network, your laptop is holding two networks at once.
If both use 192.168.1.0/24, which is what a large share of consumer routers
ship with, the laptop cannot tell which one an address belongs to. The fix is to number
your own networks out of the large private ranges, somewhere unusual.
The planner sizes each subnet to the smallest block that fits your hosts plus the network and
broadcast addresses, then packs the largest first so every block lands on its natural
boundary. It plans for IPv4 only, and it treats a /30 as the smallest
subnet.