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Cloud Resource Utilization Calculator

Blend CPU, memory and storage utilisation into one figure, then size the fleet the observed peak actually needs.

About Cloud Resource Utilization Calculator

Utilisation is blended with CPU carrying the most weight because compute pricing follows vCPU, while storage is included at a lower weight since it is cheap but frequently over-provisioned. Right-sizing converts the observed peak into an absolute demand and divides by the utilisation you are prepared to run at, so the answer keeps deliberate headroom rather than fitting the peak exactly. Average utilisation below 20% is normal and is the single largest pool of recoverable cloud spend, but resizing on averages instead of percentiles causes outages. Cost does not always scale linearly with vCPU across instance families, so verify the projected saving against your provider's pricing before acting.

Formula

Cloud Resource Utilization

blended utilisation = CPU × 0.45 + memory × 0.35 + storage × 0.20; required vCPU = provisioned vCPU × peak CPU ÷ target utilisation; reclaimable spend = spend × reclaimed vCPU ÷ provisioned vCPU.

peak CPU
95th-percentile utilisation from your monitoring, not the mean
target utilisation
The peak you are willing to run at, which sets your headroom
blended utilisation
CPU-weighted composite, because CPU is what compute pricing tracks

Worked example

With the default values below, Cloud Resource Utilization Calculator returns Blended Utilisation of 25.8%. Change any input above and every figure here is recalculated in your browser.

Inputs used

vCPUs provisionedaccepts 1–500,000 vCPU
640 vCPU
Average CPU utilisationaccepts 0–100 %
18 %
95th-percentile CPU utilisationaccepts 1–100 %
46 %
Average memory utilisationaccepts 0–100 %
32 %
Storage provisionedaccepts 0–100,000 TB
80 TB
Storage actually usedaccepts 0–100,000 TB
26 TB
Monthly spend on this fleetaccepts 0–20,000,000 USD/month
55,000 USD/month
Target peak utilisationaccepts 20–95 %
65 %

Results

Blended Utilisation
25.8%
CPU Utilisation
18.0%
Memory Utilisation
32.0%
Storage Utilisation
32.5%
vCPUs the Peak Needs
453 vCPU
Reclaimable Monthly Spend
$16,070.31
Utilisation Grade
F — Critical
Headroom Check
The peak leaves room to shrink toward the target

Step by step

  1. 1Values used
  2. 2Cloud Resource Utilization
  3. 3Blended Utilisation= 25.8
  4. 4CPU Utilisation= 18.0
  5. 5Memory Utilisation= 32.0
  6. 6Storage Utilisation= 32.5
  7. 7vCPUs the Peak Needs= 453 vCPU
  8. 8Reclaimable Monthly Spend= 16,070.31

Assumptions and limits

  • The result is derived only from the 8 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 2 decimal places, 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

How is Cloud Resource Utilization calculated?

blended utilisation = CPU × 0.45 + memory × 0.35 + storage × 0.20; required vCPU = provisioned vCPU × peak CPU ÷ target utilisation; reclaimable spend = spend × reclaimed vCPU ÷ provisioned vCPU. Utilisation is blended with CPU carrying the most weight because compute pricing follows vCPU, while storage is included at a lower weight since it is cheap but frequently over-provisioned. Right-sizing converts the observed peak into an absolute demand and divides by the utilisation you are prepared to run at, so the answer keeps deliberate headroom rather than fitting the peak exactly.

Why does Cloud Resource Utilization matter?

Average utilisation below 20% is normal and is the single largest pool of recoverable cloud spend, but resizing on averages instead of percentiles causes outages. Cost does not always scale linearly with vCPU across instance families, so verify the projected saving against your provider's pricing before acting.

What values do I need to enter?

This calculator takes 8 inputs: vCPUs provisioned, Average CPU utilisation, 95th-percentile CPU utilisation, Average memory utilisation, Storage provisioned, Storage actually used, Monthly spend on this fleet, Target peak utilisation. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Why not size to 100% of the observed peak?

The peak you measured is not the peak you will see. Sizing to a target such as 65% leaves room for growth, for traffic spikes and for the load that shifts onto the survivors when one instance fails — which is exactly when you least want to be at capacity.

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