How cloud billing works

What every line on a cloud bill is made of, how accounts or projects roll up into an invoice, the different kinds of cost, and a map of the cost tools on each provider.

Pricing units

Also called pay as you go, per hour, GB-month, per request, metering

What: Every charge is a quantity times a unit price: seconds or hours for compute, GB per month for storage, requests or invocations for serverless and APIs, GB for data transfer, tokens for AI models.
Why: Knowing the unit tells you what to change to cut the line: run fewer hours, store less, make fewer calls, move less data.

Watch out

Assuming a stopped VM costs nothing: its disks, snapshots and public IP addresses keep billing.

AWS accounts and consolidated billing

Also called AWS Organizations, management account, member account, consolidated billing

What: Each AWS account owns its resources and charges. AWS Organizations groups accounts under a management account that receives one consolidated bill and manages billing settings such as cost allocation tags.
Why: An account per team or environment allocates most cost automatically, before any tag is needed.

Watch out

Several teams sharing one account, so every split depends on perfect tagging.

List, contracted, billed and effective cost

Also called ListCost, BilledCost, EffectiveCost, ContractedCost, on-demand price

What: List is the public price. Contracted is your negotiated price. Billed is what the invoice charges for a line. Effective spreads commitments and discounts back over the usage they covered.
Why: Effective cost is fair for team reports; billed cost reconciles to the invoice. FOCUS names all four.

Watch out

Comparing teams on different cost types and drawing the wrong conclusion.

Actual versus amortised cost

Also called amortized, actual cost, cash view, accrual view

What: Actual cost shows charges when they are billed, so an upfront commitment appears as one big charge. Amortised cost spreads that payment over the months it covers.
Why: Amortised shows the real monthly run rate; actual reconciles to cash and invoices. Finance often wants both.

Watch out

An actual-cost chart with a spike in the month a commitment was bought, read as an emergency.

Hidden cost lines

Also called data transfer, NAT gateway, log ingestion, support plan, public IPv4

What: Charges compute-only estimates miss: data transfer, NAT gateways, load balancers, public IPv4 addresses, logs, snapshots, idle managed databases, marketplace software and the support plan.
Why: They often make up a large share of a small team's bill and are rarely owned by anyone.

Watch out

Trusting an estimate that lists only VMs and a database.

Billing data latency

Also called data freshness, month-end finalisation, late charges

What: Cost data arrives in batches, hours behind usage, and a month keeps changing for a few days after it ends. Microsoft starts finalising 72 hours after the billing period closes.
Why: Daily reviews look at yesterday, and month-end reports wait for data to settle.

Watch out

Publishing a month's total on the 1st and explaining a different number on the 4th.

Pricing calculators

Also called AWS Pricing Calculator, Azure pricing calculator, Google Cloud pricing calculator, cost estimate

What: Free tools from each provider to estimate a design: every resource, size, hours, storage, requests and data transfer, with assumptions written down.
Why: Estimating teaches the pricing model, and comparing the estimate with two weeks of real cost shows which assumption was wrong.

Watch out

Estimating at full production traffic for an app with a hundred users, or the reverse.

Cost tools on each provider

Also called AWS vs Azure vs GCP cost tools, equivalent cost services, FinOps tools map

What: The same FinOps job has a different tool name on each cloud. This table maps the visibility and control tools you use most.
Why: Job posts, courses and colleagues use other providers' names; the map lets you translate.

Code

Job      AWS              Azure            Google Cloud
Explore  Cost Explorer    Cost analysis    Billing reports
Export   CUR 2.0, FOCUS   Exports, FOCUS   BigQuery export
Tags     Cost alloc tags  Tags, inherit    Labels
Split    Cost Categories  Allocation rule  BigQuery views
Budget   AWS Budgets      Budgets          Budgets
Anomaly  Anomaly Detect.  Anomaly alerts   Cost anomalies
Advice   Cost Opt. Hub    Advisor          FinOps hub
K8s      Split cost data  AKS cost anal.   GKE cost alloc

Watch out

Assuming equivalent tools work the same: scope, delay and defaults differ, so check each one's docs.

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