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Cloud savings assessment register

Test a cost change against workload demand, then record the evidence, approvals and implementation needed to validate it.

Download blank CSV

ARCO engineering · Updated

Did the bill fall, or did the workload shrink?

Compare billed cost with cost per workload unit. Account for temporary credits and incremental delivery costs before interpreting a saving.

Synthetic examples, not client measurements. Calculation runs locally; export needs no account. All periods must use the same scope, length, unit and currency.

No exchange-rate conversion is applied.

After credits, for the agreed scope and period.

Use the same cost basis, currency and period length.

For example, completed requests or transactions.

Measure the same workload unit.

Add credits and delivery costs

Optional adjustments. Blank values count as zero. Add back temporary credits already deducted from your bills.

Already deducted from the billed cost; added back here.

Add back temporary credits to avoid counting them as efficiency.

Incremental fees not already included in comparison cost.

Deducted once from the first comparison period.

Read the change in context

Synthetic example: a smaller bill, less demand. Edit the values to compare your own periods.

Billed cost decrease
$2,000.00
Baseline cost at comparison demand
$5,000.00
Demand-adjusted cloud benefit
-$3,000.00
Net recurring benefit for the period
-$3,000.00
First-period net benefit
-$3,000.00

Unit cost: $0.01 → $0.016. Improvement: -60%.

A negative benefit means a higher comparable cost. This arithmetic does not establish why efficiency changed or prove realized financial savings.

Method and assumptions

Add the entered one-off credits back to billed costs. Divide each adjusted cost by its workload quantity. Multiply baseline unit cost by comparison quantity, then subtract adjusted comparison cost and any additional recurring cost. Subtract implementation cost once for the first-period result.

This linear model assumes the workload unit is a useful demand driver and scope and period lengths match. Service mix, rate changes, fixed costs, commitments, seasonality, reliability and business outcomes need separate review. It does not annualize a short observation or double-count overlapping findings.

Keep account identifiers and detailed billing evidence in your approved evidence store. Use this aggregate comparison alongside the savings register.

What to record

Finding and scope

Record a finding ID, cloud, workload alias, service, region and accountable owner. Keep account IDs and private billing records in your restricted evidence store.

Baseline and comparison

Record billing currency, measurement windows, usage quantity, unit, rate basis, credits, refunds and commitment treatment. Compare like-for-like periods.

Decision and delivery

Record estimated opportunity, overlapping findings, engineering cost, risk, approval, change reference, rollback and implementation date.

Validation

Record comparable post-change cost, demand adjustments, measured benefit, evidence reference and reviewer. Leave realized savings blank until verified.

How to use the template

  1. Export billing evidence with a consistent cost basis and reconcile it to the billed population.
  2. Create one row per independent opportunity. Flag overlaps before summing a portfolio.
  3. Agree a change owner and reliability checks before implementation.
  4. Measure post-change usage and cost; explain credits, rates and demand differences.
  5. Keep rejected findings and exceptions so the next review does not repeat the same assumptions.

This is an empty operating template, not an automated recommendation engine or a statement of ARCO client savings. A finance owner must approve the measurement basis.

AWS Cost and Usage Reports; Google Cloud detailed billing export schema; FinOps Foundation: Unit Economics.

CSV field reference

A header-only file: fill it with your approved evidence and decisions. No client records or example savings are embedded.

  • finding_id
  • cloud
  • workload_alias
  • service
  • owner
  • baseline_start
  • baseline_end
  • currency
  • cost_basis
  • baseline_usage
  • usage_unit
  • baseline_cost
  • credit_adjustment
  • commitment_treatment
  • estimated_monthly_saving
  • overlap_group
  • implementation_cost
  • risk
  • approval_reference
  • change_reference
  • rollback_reference
  • implementation_date
  • comparison_start
  • comparison_end
  • normalized_comparison_cost
  • measured_monthly_benefit
  • evidence_reference
  • reviewer
  • status

Worked engineering guides

Reference or share this resource

Use this reference in a report or discussion. It includes the resource’s title, update date and permanent page URL.

Apply it to your environment

AWS engineering scopeGoogle Cloud engineering scope
EKS and GKE cost versus reliability checklist