← All tools
CIDR Allocation Planner
Allocate IPv4 subnets using VLSM, visualize address use, and export a reproducible plan.
IPv4 scope: this planner intentionally does not claim IPv6 support. Host requests include the selected gateway when one is shown. `/31` treats both addresses as usable point-to-point endpoints; `/32` treats its single address as usable.
Parent and strategy
Every allocation is aligned to its own CIDR boundary. Preserving order can create gaps.
Subnet requests
Format:
name, usable-host-count or name, /prefix. Names must be unique and use letters, digits, spaces, dots, underscores, or hyphens. Up to 500 requests.Allocation plan
0allocated addresses
0unallocated addresses
0unused host capacity
Noneoverlaps
| Name | Request | CIDR | Network | First usable | Last usable | Broadcast | Gateway | Usable | Waste |
|---|