OhMyCalc

Instance Sizing Calculator

Get recommended vCPU, RAM, and instance type based on your peak CPU usage, memory needs, and storage requirements. Right-size your cloud instances.

How to Use the Instance Sizing Calculator

  1. Enter peak CPU utilization percentage.
  2. Enter peak RAM requirement in GB.
  3. Enter storage requirement in GB.
  4. Click Calculate to get recommended instance specifications.

使用例

計算式

Recommended vCPU = ceil(peak CPU% / 25). Recommended RAM = peak RAM × 1.3 (30% headroom).

よくある質問

What is right-sizing?
Right-sizing means selecting the smallest instance that meets performance requirements, avoiding over-provisioning.
Why add 30% RAM headroom?
Headroom prevents OOM kills under unexpected traffic spikes and leaves room for OS and monitoring agents.
How do I measure peak CPU?
Use monitoring tools (CloudWatch, Datadog) to capture 95th percentile CPU usage over representative traffic periods.