NetOpsT

Cloud CIDR Capacity Calculator

Calculate usable address capacity for AWS, Azure and GCP subnets.

Runs locally

CLOUD / CAPACITY

Cloud CIDR Capacity Calculator

Subnet capacity

Standard AWS / Azure subnets and GCP primary IPv4 ranges.

10.20.0.0/24

Capacity fits
Total addresses
256
Provider reserved
5
Usable addresses
251
IPs including growth
240
Remaining after growth
11
Suggested subnet size
/24

Assignable range: 10.20.0.410.20.0.254

Planning scope

This is capacity math, not deployment validation. Count all IP-consuming interfaces, private endpoints and services, not just VMs. Service-specific minimum sizes, overlaps, routes and BYOIP exceptions are not checked. GCP secondary ranges use different reservations. A suggested prefix does not allocate a free CIDR.

Read AWS subnet documentation

Cloud TOOL

Cloud CIDR Capacity Calculator

Calculate usable address capacity for AWS, Azure and GCP subnets.

When to use this tool

Use it to avoid running out of IP addresses in cloud networks.

Use it in three steps

  1. Choose the provider and CIDR prefix to compare reserved and usable addresses.
  2. Review the calculated values against your environment and its requirements.
  3. Copy or document the result only after validating it for production use.

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