Online Tool Store
IP Allocation Planner
Enter a network block and subnet host requirements to generate a full CIDR allocation plan. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Allocation plan
Example shown — replace it with your own network block and subnet needs.
How it works
- Enter your network block and the subnets you need, with host counts.
- Each subnet is sized to the smallest CIDR block that fits.
- See the full allocation plan with CIDR ranges and usable hosts.
Planning sorts subnets largest to smallest, then carves each one out of the available address space at the tightest CIDR size that still fits the requested host count — standard subnetting practice for minimizing wasted addresses.
FAQ
Is my network data uploaded anywhere?
No. Planning happens entirely in your browser — nothing is sent to a server.
How does it decide each subnet's size?
It finds the smallest CIDR block that fits your requested number of usable hosts for each subnet, sorted largest to smallest to minimize wasted addresses.
What if my subnets don't fit in the network block?
The tool flags it immediately, showing how many addresses you're short so you can adjust your requirements or use a larger block.
Does it account for network and broadcast addresses?
Yes — the usable host count for each subnet already excludes the network and broadcast addresses, matching real-world usable capacity.
How we compare
| Feature | Online Tool Store | Manual subnetting by hand | Single-subnet calculators |
|---|---|---|---|
| Plans multiple subnets at once | ✓ | Slow, error-prone with several subnets | One subnet per calculation |
| Free, no setup | ✓ | ✓ | ✓ |
A single-subnet calculator only handles one block at a time. IP Allocation Planner lays out an entire network's subnets in one pass.