List, billed, effective and amortized cost are four answers to the question "what did this cost": what the usage would have cost at the public price, what the provider invoices in this period, what the usage is worth after every discount, and how a commitment paid up front is spread across its term. The four diverge as soon as reservations, Savings Plans, negotiated prices or credits are involved. A report that mixes them compares the invoice with consumption and explains jumps that do not exist.
How it works
FOCUS, the open billing data specification from the FinOps community, defines the measures independently of any provider; version 1.4 is current:
- ListCost: list unit price times pricing quantity, the cost before any discount.
- ContractedCost: contracted unit price times pricing quantity, after negotiated prices but before commitment discounts.
- BilledCost: the cost of a charge as the invoice issuer invoices it in the billing period. For a purchase that is the portion invoiced in the period; for usage it excludes any portion a related purchase covers. The sum per invoice number must match the invoice within rounding.
- EffectiveCost: the cost after every pricing adjustment, attributed to the resources used. For usage it includes the recognised portion of the purchase that covers it; the covering purchase itself is set to zero so that nothing counts twice.
FOCUS has no column called amortized cost: what the providers call amortized is the spreading of a purchase across the usage it covers, and that is exactly what EffectiveCost carries. Effective cost and amortized cost therefore name the same measure in practice; "effective" stresses the discounts, "amortized" the spreading.
AWS
Cost Explorer offers five views. Unblended costs show the cost of usage, with discounts as their own line items. Amortized costs spread the upfront and monthly reservation fees across the billing period; without that view a reservation fee appears as a spike on the day it is charged, with it as an effective daily rate, and the unused portion sits on the first of the month in the daily view. Blended costs are the average across the accounts of an organization. Net unblended and net amortized costs add discounts on top. CUR 2.0 carries the same measures as columns: line_item_unblended_cost, line_item_blended_cost and, only when the account has a discount in the period, line_item_net_unblended_cost; the spreading sits in reservation_effective_cost and savings_plan_savings_plan_effective_cost, and the line item type separates kinds of charge, among them Usage, DiscountedUsage, Fee, RIFee, SavingsPlanUpfrontFee, SavingsPlanRecurringFee, SavingsPlanCoveredUsage, SavingsPlanNegation, Credit, Refund and Tax. Which export to pick is the subject of AWS CUR 2.0 or FOCUS 1.2: choose the right cost export.
Azure
Cost Management keeps two datasets. Actual cost reconciles to the invoice: a reservation purchase is a line of charge type Purchase, and the effective price of the usage that receives the discount is zero. Amortized cost has no purchase lines; instead the covered usage carries the prorated price of the reservation as its effective price, and unused hours appear as UnusedReservation. Cost analysis shows actual cost by default, and exports come as actual, amortized and FOCUS, which combines the two. Each row also carries the pay-as-you-go price (the list price), the unit price with the negotiated discount, and the effective price actually paid.
Google Cloud
The billing export to BigQuery has no switch. The cost column is the price under the applicable consumption model including negotiated discounts, cost_at_list the list price, and credits holds credits as negative amounts with one of several types, among them COMMITTED_USAGE_DISCOUNT, SUSTAINED_USAGE_DISCOUNT, DISCOUNT, PROMOTION, FREE_TIER. Net cost is cost plus credits. A commitment is charged hourly for the whole term regardless of use; under proportional attribution, the default, the fee is attributed to projects in proportion to the usage they cover, and the unattributed remainder sits at the billing account level. Setting up the export is covered in Set up Google Cloud billing export for cost reporting.
What it means for your cost
An All Upfront reservation shows the whole problem. In billed cost its full price lands on the invoice on the day of purchase, and the covered usage then appears at a rate of zero. In effective cost the purchase disappears and reappears hour by hour against the usage that consumes it; whatever stays unused stays with the account that holds the reservation. The total over the term is the same in both views; the distribution across months and teams is not.
From that follows which measure answers which question:
| Question | Measure |
|---|---|
| What do we pay this month, and is the invoice right | billed cost: BilledCost, AWS unblended or net unblended, Azure actual, on Google the invoice month |
| What does a team, a product or a service really cost | effective cost: EffectiveCost, AWS net amortized, Azure amortized, on Google cost plus credits |
| What do negotiated prices and commitments earn us | the gap between list, contracted and effective cost |
| Did a saving work | the effective cost of the same resource before and after the change |
A cost report to a team that holds no reservations of its own shows effective cost; finance receives billed cost, because only that reconciles to the invoice. A report that needs both shows both columns and names them.
Where it goes wrong
- Summing a mixed export. Symptom: the total exceeds the invoice by the commitment fees. Cause: the CUR holds the fee lines and the spread effective cost side by side, and adding
line_item_unblended_costtoreservation_effective_costcounts the purchase twice; the same happens when Azure actual and amortized land in one table. - Comparing periods across measures. Symptom: last month from the amortized report, this month from the invoice, and the trend shows an increase that is not there. Cause: the same money is a spike in one view and a spread in the other.
- Reading an upfront fee as a cost increase. Symptom: an anomaly on the purchase day, an escalation, a reversal that improves nothing. Cause: the report ran on billed cost; on effective cost the day is unremarkable.
- Credits counted twice. Symptom: the saving is larger than the invoice allows. Cause: on Google, credits are separate lines in the cost table but a field per line in the export; on AWS, credits are negative line items inside unblended cost and are also listed on the Savings tab. Adding the two presentations deducts the same amount twice.
Sources
Read on 2026-10-15. FOCUS 1.4 Column library, List Cost, Billed Cost, Effective Cost, Contracted Cost; AWS Choosing advanced options in Cost Explorer, CUR 2.0 line item columns, Reservation columns, Savings Plans columns, Understanding your bill; Microsoft Understand Azure reservations usage for Enterprise Agreement and Microsoft Customer Agreement, Create and manage exports, Understand usage details fields; Google Cloud Structure of Standard data export, Attribution of committed use discount fees and credits, Committed use discounts for Compute Engine.