The Cloud Subnet Calculator is a specialized utility for network architects and DevOps
engineers to plan CIDR divisions for AWS, Azure, and GCP.
Features
- Recursive Splitting: Easily divide large CIDR blocks into smaller subnets.
- Visual Feedback: See the hierarchy of your network as you design it.
- Cloud Validation: Built-in rules for AWS, Azure, and GCP (identifying reserved IPs,
limits, etc.).
- Exportable: Generate Markdown tables or JSON exports of your design.
Usage Guide
1. Starting a Design
Enter a base CIDR block (e.g., 10.0.0.0/16) in the input field. This acts as the root of
your network tree.
2. Subnetting
- Divide: Click the Divide icon on any row to split it
into two equal halves (e.g., a /24 becomes two /25s).
- Join: If you change your mind, click the Join icon to
merge two adjacent, empty subnets back together.
3. Labeling and Organization
Click the Edit icon to assign a name to a subnet (e.g., "Web Tier", "AKS
Cluster"). This is crucial for generating readable documentation later.
4. Selecting a Provider
Toggle between AWS, Azure, and GCP modes. The tool
will automatically update the "Usable IPs" count based on the provider's reserved IP rules (e.g., Azure
reserves 5 IPs per subnet).
5. Export to Documentation
Once your design is ready, use the Markdown Export feature.
- Click the Markdown button in the toolbar.
- Copy the generated table directly into Confluence, GitHub/GitLab
Wikis, or Notion.
- The output is formatted as a clean Markdown table, compatible with most documentation platforms.
Pro Tip: You can paste this generated Markdown table back into the tool later to
restore your session!
6. Save & Iterate
Since there is no backend database, "saving" works differently:
- Share URL: Copy the URL from the address bar (or use the Share button). It contains
the entire state of your design (compressed). Bookmark it to return later.
- Json Export: You can download the raw JSON for your subnet tree, and drag and drop
it back to tool to resume your work.