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Idle Resource Cost Calculator

Price instances sitting below a CPU threshold plus their attached disks and idle addresses, and what scheduling would save.

About Idle Resource Cost Calculator

An idle instance costs more than its compute line, because attached disks bill in full whether the instance runs or not and reserved public addresses are charged precisely when nothing is using them. Scheduling is costed separately: it does not delete anything, it just stops paying for the roughly 680 hours a month that a 50-hour workload is not needed. Stopping an instance removes the compute charge but not the storage charge, which is why teams report far smaller savings than they expected after a shutdown campaign. Confirm which meters keep running while stopped on your provider — the behaviour differs between compute, disk, address and licence charges.

Formula

Idle Resource Cost

idle cost = idle instances × rate × 730 + idle instances × attached GB × storage rate + unattached addresses × address rate × 730; scheduling saving = schedulable instances × rate × (730 − needed hours).

needed hours
Working hours per week multiplied by 4.345 weeks in an average month
attached storage
Disks that keep billing at full rate even while the instance is stopped
CPU threshold
The utilisation floor below which an instance is treated as idle

Worked example

With the default values below, Idle Resource Cost Calculator returns Monthly Cost of Idle Resources of $1,976.67. Change any input above and every figure here is recalculated in your browser.

Inputs used

Instances in scopeaccepts 1–100,000 instances
40 instances
Instances below the CPU thresholdaccepts 0–100,000 instances
12 instances
Idle CPU thresholdaccepts 0.5–50 %
5 %
Instance rateaccepts 0–200 USD/hour
0.192 USD/hour
Hours in the monthaccepts 1–744 hours
730 hours
Hours per week the workload is neededaccepts 0–168 hours
50 hours
Instances that could be scheduled offaccepts 0–100,000 instances
18 instances
Attached storage per instanceaccepts 0–100,000 GB
200 GB
Block storage rateaccepts 0–5 USD/GB-month
0.1 USD/GB-month
Unattached public addressesaccepts 0–100,000 addresses
15 addresses
Idle address rateaccepts 0–5 USD/hour
0.005 USD/hour
Total monthly cloud spendaccepts 0–20,000,000 USD/month
60,000 USD/month

Results

Monthly Cost of Idle Resources
$1,976.67
Saving from Scheduling Off-Hours
$1,772.06
Idle Compute
$1,681.92
Storage Attached to Idle Instances
$240.00
Unattached Address Charges
$54.75
Hours Nobody Needs the Workload
513 hours
Annual Cost of Idle Resources
$23,720.04
Idle Share of Total Spend
3.3%
Recommended First Move
Stop or delete the 12 instances under 5% CPU, then schedule the rest

Step by step

  1. 1Values used
  2. 2Idle Resource Cost
  3. 3Monthly Cost of Idle Resources= 1,976.67
  4. 4Saving from Scheduling Off-Hours= 1,772.06
  5. 5Idle Compute= 1,681.92
  6. 6Storage Attached to Idle Instances= 240.00
  7. 7Unattached Address Charges= 54.75
  8. 8Hours Nobody Needs the Workload= 513 hours

Assumptions and limits

  • The result is derived only from the 12 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax 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 Idle Resource Cost calculated?

idle cost = idle instances × rate × 730 + idle instances × attached GB × storage rate + unattached addresses × address rate × 730; scheduling saving = schedulable instances × rate × (730 − needed hours). An idle instance costs more than its compute line, because attached disks bill in full whether the instance runs or not and reserved public addresses are charged precisely when nothing is using them. Scheduling is costed separately: it does not delete anything, it just stops paying for the roughly 680 hours a month that a 50-hour workload is not needed.

Why does Idle Resource Cost matter?

Stopping an instance removes the compute charge but not the storage charge, which is why teams report far smaller savings than they expected after a shutdown campaign. Confirm which meters keep running while stopped on your provider — the behaviour differs between compute, disk, address and licence charges.

What values do I need to enter?

This calculator takes 12 inputs: Instances in scope, Instances below the CPU threshold, Idle CPU threshold, Instance rate, Hours in the month, Hours per week the workload is needed, Instances that could be scheduled off, Attached storage per instance, Block storage rate, Unattached public addresses, Idle address rate, Total monthly cloud spend. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Is low CPU enough to call an instance idle?

No. Database replicas, log shippers and licence servers can sit near zero CPU while being critical. A safe rule combines low CPU with negligible network traffic, no active sessions and an owner confirmation, which is why the tag and owner data matters as much as the metric.

Idle Resource Cost Calculator | Calcrivo