VPA Recommendation Calculator
Estimate Vertical Pod Autoscaler recommended requests based on historical usage.
About VPA Recommendation Calculator
The Vertical Pod Autoscaler's recommender tracks a decaying histogram of usage and targets a high percentile (commonly p95 or p90) plus a margin, rather than the raw peak, to avoid overreacting to one-off spikes. This calculator reproduces that logic in simplified form — applying a percentage margin over p95 usage — and compares the result to the pod's current request to show whether VPA would recommend scaling up or down.
Formula
recommended = p95Usage × (1 + marginPercent / 100)
- U_{95}
- 95th percentile CPU usage in millicores
- m
- Safety margin percentage
- R
- VPA-recommended CPU request in millicores
Worked example
With the default values below, VPA Recommendation Calculator returns VPA-Style Recommended Request of 345. Change any input above and every figure here is recalculated in your browser.
Inputs used
- P95 CPU Usageaccepts 1–64,000 millicores
- 300 millicores
- Safety Marginaccepts 0–200 %
- 15 %
- Current CPU Requestaccepts 1–64,000 millicores
- 200 millicores
Results
- VPA-Style Recommended Request
- 345 millicores
- Change vs Current Request
- 145 millicores
- Change vs Current Request
- 72.5%
- Recommended Direction
- increase
Step by step
- 1Recommended = p95 usage × (1 + margin%)= 345m
- 2Delta vs current request= 145m (72.5%)
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why does VPA use p95 instead of peak usage?
Peak usage can be a single outlier event; p95 usage reflects sustained near-peak behavior while filtering out one-off spikes, giving a recommendation that's stable across normal traffic variance rather than chasing the single highest data point ever seen.
What update modes does VPA support?
Off (recommend only, no changes applied), Initial (apply only at pod creation), and Auto/Recreate (VPA evicts and recreates pods with new resource values) — always verify update mode before assuming VPA will change running pods automatically.
Can I run VPA and HPA together on CPU?
Not safely on the same metric — VPA adjusting CPU requests while HPA scales replicas based on CPU utilization creates a feedback loop. Common practice is VPA on memory only, paired with HPA on CPU or custom metrics.