SNS Delivery Volume Estimator

This calculator is the SNS delivery-volume workflow page: use it to translate publish count, matched fan-out, and retry behavior into monthly delivery attempts before pricing starts. It does not own SNS pricing, downstream SQS, Lambda, or email cost, or full messaging architecture decisions.

Maintained by CloudCostKit Editorial Team. Last updated: 2026-01-30. Editorial policy and methodology.

Best next steps

Use this calculator for the first estimate, then validate the answer with the closest guide or companion tool.

AWS SNS cost calculator Guide: estimate SNS deliveries Guide: SNS pricing

Inputs

Publishes (per month)
Total messages published to the topic.
Subscriptions per topic
Average subscribers for the topic or workload.
Match rate (%)
Percent of subscriptions that receive each publish.
Retry multiplier (%)
Buffer for failed deliveries and retries.
Peak publish multiplier (%)
Applies to publish volume only.
Scenario presets
Use publishes and deliveries in the AWS SNS cost calculator.

Results

Matched fan-out
10
Baseline deliveries
1,200,000,000
Total deliveries
1,320,000,000
Retry multiplier
110%
Match rate
40%
Baseline vs peak
ScenarioDeliveriesFan-outRetry
Baseline1,320,000,00010110%
Peak2,376,000,00010110%

Keep this page narrow. The question here is only whether publish count, matched fan-out, and retry behavior are measured well enough to produce a defendable delivery baseline before the main SNS cost model takes over.

SNS delivery volume is a publish-to-fan-out multiplier problem

This page exists to translate publish activity into actual delivery attempts. The key levers are not only how many messages are published, but how many subscriptions match each publish and how much retry behavior expands the final delivery count.

  • Publishes: the source traffic entering the topic.
  • Matched fan-out: the filtered delivery multiplier after subscription rules are applied.
  • Retry expansion: the extra delivery attempts caused by unhealthy or delayed endpoints.

Where SNS estimates usually drift

  • Total subscriptions are counted even though only a subset actually matches most publishes.
  • Retry behavior is ignored, so endpoint failures do not show up in the delivery estimate.
  • Multiple topics are blended together and hide which topic actually drives fan-out.
  • Teams think in publish count, but the bill grows with delivery multiplication.

What to review before feeding this into the main SNS calculator

  • Measure matched fan-out after filter policies instead of counting every subscriber equally.
  • Model unhealthy endpoints separately if retries are common during incidents.
  • Split high-volume topics so one noisy path does not distort the whole estimate.
  • Treat this page as a delivery estimator, not a full downstream system cost model.

Next steps

AWS SNS cost calculator Guide: estimate SNS deliveries

Example scenario

  • 120M publishes/month, 25 subscriptions, 40% match rate, 110% retry buffer.
  • Peak scenario for incident-driven delivery spikes.

Included

  • Matched fan-out from subscriptions per topic and match rate.
  • Baseline deliveries from publishes and fan-out.
  • Retry multiplier to account for failed deliveries.
  • A delivery-volume handoff for the main SNS calculator or pricing guide.

Not included

  • SNS pricing and full bill conversion.
  • Downstream service costs (SQS, Lambda, email).
  • Full messaging architecture decisions across topics and subscribers.

How we calculate

  • Matched fan-out = subscriptions x match rate.
  • Baseline deliveries = publishes per month x matched fan-out.
  • Total deliveries = baseline deliveries x retry multiplier.

FAQ

Should I count subscriptions that rarely match?
No. Use matched fan-out after filter policies so you only count subscribers that receive each publish.
Do retries affect delivery volume?
Yes. If endpoints fail, retries increase delivery attempts and total request volume.
What if I have multiple topics?
Run the estimator per topic or use weighted averages for publishes and fan-out.

Related tools

AWS SNS cost calculator Guide: estimate SNS deliveries Guide: SNS pricing

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Disclaimer

Educational use only. Not legal, financial, or professional advice. Results are estimates based on the inputs and assumptions shown on this page. Verify pricing and limits with your providers and documentation.

Last updated: 2026-01-30. Reviewed against CloudCostKit methodology and current provider documentation. See the Editorial Policy .