Server Capacity Calculator – vCPU and RAM Planning
Calculate server capacity requirements for web applications and databases.
About This Calculator
Calculate server capacity requirements for web applications and databases. Use the calculator above for instant results.
Worked Examples
- CPU: 500×50/1000 = 25 core-seconds → 25 vCPUs
- RAM: 500×10MB = 4.88 GB → 5 GB RAM
Answer: ~25 vCPUs / 5 GB RAM
- CPU: 20 vCPUs | RAM: 2 GB
Answer: 20 vCPUs / 2 GB
- CPU: 10 vCPUs | RAM: 5 GB
Answer: 10 vCPUs / 5 GB
Who Uses This Calculator?
Right-size application servers.
Capacity planning for deployments.
Infrastructure sizing.
Cloud budget planning.
Common Mistakes to Avoid
❌ CPU time varies by operation
A database query might use 500ms CPU while a static response uses 1ms. Profile real CPU time for accuracy.
❌ Memory includes app overhead
Add base OS (0.5-1 GB) + application base memory + per-connection memory. Real RAM needs are typically higher.
Frequently Asked Questions
Headroom rule?
Plan for 2× calculated needs. Provision at 50% capacity so you have room to scale up before hitting limits.
Kubernetes autoscaling?
Horizontal Pod Autoscaler scales pod count. Cluster autoscaler adds nodes. Target 60-70% CPU/memory utilization for smooth scaling.
Database is usually the bottleneck?
Application servers scale horizontally easily. Database typically requires more careful planning — consider read replicas and sharding early.