Interactive workbench
CIDR / Subnet Calculator
Calculate networks, host ranges, and subnet plans without leaving the browser.
Can this address space support the environments, zones, and subnet splits we need before we provision anything?
How to use & What you leave with
Configuration Suite
Surgically adjust parameters for CIDR / Subnet Calculator
Methodology
This tool automates the core architectural decisions required for high-performance scale. It eliminates spreadsheet errors and gut feeling by using post-2026 optimized algorithms.
Output Precision
- Surgical accuracy for production loads
- Ready for direct export to Terraform/Docs
IPv4 CIDR — e.g. 10.42.0.0/16 for a VPC.
Subnet size — e.g. /24 for 256 addresses per subnet.
Number of AZs for the allocation plan.
e.g. prod, staging, dev — determines subnets needed.
PRO TIP: Changes reflect in real-time. Use shortcuts for fast navigation.
Usable hosts
65,534
/20 subnets
16
Addresses / subnet
4,096
Subnets needed
9
Utilization
56%
Key Insights
- Parent network: 10.42.0.0/16. Splitting to /20 yields 16 subnets of 4,096 addresses each.
- 9 subnets needed for 3 AZs × 3 environments — fits with 7 subnets to spare.
- Healthy address space headroom for future expansion.
Actionable Next Steps
- Allocation plan fits — export the Terraform snippet and integrate into your VPC module.
- Review the allocation against your landing zone design and security group segmentation.
- Reserve at least 2 spare subnets for future services, endpoints, or transit gateway attachments.
Analysis Metrics
Benchmarks & Comparison
| Prefix | Subnets | Addrs/subnet | Usable/subnet | Fits 9 needed |
|---|---|---|---|---|
| /17 | 2 | 32,768 | 32,766 | No |
| /18 | 4 | 16,384 | 16,382 | No |
| /19 | 8 | 8,192 | 8,190 | No |
| /20 | 16 | 4,096 | 4,094 | Yes |
| /21 | 32 | 2,048 | 2,046 | Yes |
| /22 | 64 | 1,024 | 1,022 | Yes |
| /23 | 128 | 512 | 510 | Yes |
| /24 | 256 | 256 | 254 | Yes |
Actionable Exports
Decision Log
This tool automates the core architectural decisions required for high-performance scale.
Surgical Precision
Eliminate spreadsheet errors and gut feeling with post-2026 AI.
Seamless Workflow
Move results straight to Terraform, Jira, or Confluence.
The Lab Result
Post-2026 Audit Complete
This workflow has been surgically optimized by AutonomOps AI for Architecto Power Users.
FAQ
Questions teams ask before they adopt this workflow.
When should teams use CIDR / Subnet Calculator?
This tool is most useful when the team needs an answer they can carry into diagrams, documentation, and design reviews without rewriting the same context three times.
Who benefits most from CIDR / Subnet Calculator?
Architects, platform teams, and technical leads benefit most because they need explicit assumptions, clear review cues, and artifacts that survive implementation handoff.
How does CIDR / Subnet Calculator connect back to Architecto?
Architecto uses the free content surface as the top of a larger workflow. Once the team needs richer diagrams, schema visibility, change comparison, or technical documentation, the matching product module keeps the same decision context alive.
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Comparison
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Continue in Architecto
Use the exported artifact from CIDR / Subnet Calculator as the first review input, then move into Architect Ai when the team needs a deeper design, diagram, or review workflow.
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