Network Planner
Review an IPv4 or IPv6 pool, find overlapping ranges and free gaps, and allocate CIDR blocks. Calculations run locally in your browser.
Address plan
A single IPv4 or IPv6 CIDR. Host bits are normalized to the network boundary.
Returns the first aligned block that fits in the pool and avoids existing networks.
One CIDR per line. An optional label can follow a comma or vertical bar.
One positive host count per line: name, hosts (or just a number).
Provider reservations apply to IPv4 subnet counts; they do not model provider-specific IPv6 rules.
A share link contains the pool, network list, and VLSM requests you enter. Do not share private network information unintentionally.
Pool summary
Analyze a plan to see its results.
Existing networks and overlaps
No analysis yet.
Free gaps in the pool
No analysis yet.
VLSM allocation
| Request | Hosts requested | Allocated subnet | Address range | Usable addresses |
|---|---|---|---|---|
| No allocation yet. | ||||
How the planner counts addresses
IPv4 VLSM allocations reserve the network and broadcast addresses when sizing a subnet. IPv6 requests use the full address count. The cloud options subtract the documented count of reserved IPv4 addresses per subnet; they do not check provider quotas, routing limits, or other platform-specific rules.
Overlap, gap, and allocation results describe only the CIDRs entered here. They are planning calculations, not a check of live cloud or on-premises configuration.