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Cost Analysis: Forecast and Cost Anomalies

Overview​

Cost Analysis answers the recurring question: "Is this spend change real, and what caused it?" It charts Azure spend per subscription, marks days where spend broke from its usual pattern, explains which services drove the change, and projects spend for the next 90 days.

In the Spotto Portal, open your company and go to Investigate -> Cost -> Cost Analysis.

How to read it​

Example daily spend chart for one subscription: cost bars, a usual-pattern line, a dashed projected-spend line after today, and a marked anomaly on 20 September. Selecting the anomaly shows actual spend of $1,650, a change of +$910 and usual spend of $740; why it happened, with Virtual Machines at 82% of the increase and Storage at 11% (up to three drivers, until they explain 90% of the change); and what to check: detection notes about the resources behind the change, grouped by service. Controls: pick one or more subscriptions, each with its own charts and currencies never added together; periods Daily (7 days), 30 days, 90 days, 90 days with forecast and 12 months; only show charts with anomalies; and Focus forecast, which compares projected spend with the budget: on track under 95%, at risk 95–100%, over budget above 100%.Example daily spend chart for one subscription: cost bars, a usual-pattern line, a dashed projected-spend line after today, and a marked anomaly on 20 September. Selecting the anomaly shows actual spend of $1,650, a change of +$910 and usual spend of $740; why it happened, with Virtual Machines at 82% of the increase and Storage at 11% (up to three drivers, until they explain 90% of the change); and what to check: detection notes about the resources behind the change, grouped by service. Controls: pick one or more subscriptions, each with its own charts and currencies never added together; periods Daily (7 days), 30 days, 90 days, 90 days with forecast and 12 months; only show charts with anomalies; and Focus forecast, which compares projected spend with the budget: on track under 95%, at risk 95–100%, over budget above 100%.
  • Charts show daily spend or monthly spend. On a monthly chart the current month is marked as month to date.
  • The forecast chart also draws Expected spend, the model's fit over past days, so you can see how well the projection tracks reality.
  • Each subscription card also shows Unusual days, last 7 days and Spend, last 30 days.
  • Anomalies are tied to the chart's date range. A card with anomalies shows View N anomalies; select it, or the chart, to open the details.
  • Detection uses several methods rather than a single threshold. A driver list only appears when the billing data can attribute the change to services or resources.

Turn cost evidence into a decision​

Select Business Value beside Notes, the filters, and the subscription selector. The brief combines loaded-scope coverage, recent anomalies, 30-day spend, and forecast availability without combining currencies into an unsafe total.

Generate tailors only the narrative for permitted users and saves it to the exact scope. Clear removes that saved narrative and immediately restores the standard Business Value content without deleting Customer Context or changing live facts. Regenerate when evidence changes. Above 100 subscriptions, the curated live brief remains available without tailoring.

Use it to agree:

  • which anomalies or sustained movements need investigation now
  • the budget, forecast-variance, or daily anomaly thresholds that require action
  • the Spotto cost alerts, notification destinations, triage owner, and response cadence that provide early detection

Unexplained movement can continue compounding until routine billing review. The brief therefore asks for an owned intervention before month-end, while treating forecasts and anomaly signals as evidence to validate rather than invoice guarantees.

Export​

Export sits next to Business Value:

  • Data (CSV): the chart points for the active period filters, plus anomaly evidence and notes.
  • Report (Word): a FinOps report with an executive summary, monthly cost, month-to-date and forecast evidence, anomaly windows, recurring drivers and suggested investigations.

Exports use every successfully loaded subscription you selected and keep currencies separate.

How it differs from Azure-native cost views​

Azure Cost Management is the source of truth for billing data and is built for reporting and exploration. Cost Analysis is built for investigation: fixed time windows, a forecast, and anomalies explained against usual spend with their drivers. When you need resource- or tag-level detail, continue in Cost Tree or Resources.

Limitations​

  • Not real-time: charts update after billing data syncs, and provider billing data can lag by days.
  • Forecasts are directional: use them for planning and trend checks, not precise accounting.
  • Anomaly detection is probabilistic: a person should confirm anything expensive.

For details on actual, retail, estimated, and blended pricing, see the Pricing FAQ.

Troubleshooting​

"We don't have cost analysis for this subscription yet"​

Likely causes: the subscription hasn't completed its first billing sync, or Azure billing export isn't connected.

How to fix:

  1. Confirm the subscription is connected and syncing in Spotto, and that billing export is connected.
  2. Wait for the next billing sync and retry.
  3. If it persists, capture the subscription ID and contact support.

"We couldn't load cost analysis data"​

Likely causes: a temporary service issue, or the subscription isn't accessible in your current company context.

How to fix: select the subscription again, then use Try again. If it continues, capture the error text and time and contact support.

"Billing data may be out of date" or "Showing the last successfully processed billing data"​

The charts are usable but may not include the latest sync. The callout says the date billing data is available through. Refresh after the next sync completes.

"Billing data is unavailable" or "Cost analysis is temporarily unavailable"​

Spotto couldn't verify the latest billing analysis, so it hides the charts and anomalies rather than showing incomplete data. Wait for the retry countdown, then try again. If it continues after the next cloud sync, rerun the sync or contact your Spotto administrator. Other selected subscriptions still show their charts.

"No billing activity in the checked scope"​

Spotto found no cost activity for the subscription, so it doesn't draw zero-value charts.

"We don't have chart data yet" or "We couldn't load this chart"​

One chart isn't ready or failed to load. Use Retry chart, or check the other periods; they can become available at different times.

"No unusual spend detected for this period"​

Nothing in that period moved far enough from usual spend. Check a longer period to see whether the change is gradual, or use Cost Tree to see whether a service or resource changed without triggering an anomaly.

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