CloudTrail Storage Calculator
Size CloudTrail data event charges, compressed S3 storage across a retention window, extra trail copies and Lake ingestion.
About CloudTrail Storage Calculator
CloudTrail gives you one free copy of management events per account, so the cost almost always comes from data events, which fire once per S3 object or Lambda invocation and can be thousands of times more numerous. Storage grows linearly until the retention window fills, so the steady-state figure is the monthly volume multiplied by the retention months, not just one month. Confirm the current data event and Lake prices for your region. Turning on S3 data events across every bucket is the classic way to add a four-figure monthly line item overnight — scoping them to the buckets and prefixes that actually need an audit trail is what keeps CloudTrail affordable.
Formulas
CloudTrail Storage
cost = data events ÷ 100,000 × event price + extra trails × management events ÷ 100,000 × copy price + compressed GB held × S3 price, plus Lake ingestion if enabled.
- data event
- Object-level or function-level activity such as S3 GetObject or Lambda Invoke
- management event
- Control-plane API call; the first trail copy is free
- steady state GB
- Monthly compressed volume × retention months, once the window is full
Retention accumulation
steady-state GB = total events × event KB ÷ 1,048,576 × compressed share × retention months.
Worked example
With the default values below, CloudTrail Storage Calculator returns Estimated Monthly Cost of $54.34. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Data events per monthminimum 0 events
- 50,000,000 events
- Management events per monthminimum 0 events
- 5,000,000 events
- Additional trails beyond the firstaccepts 0–10 trails
- 0 trails
- Average event record sizeaccepts 0.1–256 KB
- 1.5 KB
- Retention in S3accepts 1–120 months
- 12 months
- Compressed size as a share of rawaccepts 1–100 %
- 20 %
- Also ingest into CloudTrail Lake
- No
- Data event price per 100,000 eventsminimum 0 USD
- 0.1 USD
- Extra-copy management event price per 100,000minimum 0 USD
- 2 USD
- S3 storage price per GB-monthminimum 0 USD
- 0.023 USD
- CloudTrail Lake ingestion price per GBminimum 0 USD
- 2.5 USD
Results
- Estimated Monthly Cost
- $54.34
- Data Event Cost
- $50.00
- Extra Trail Copy Cost
- $0.00
- S3 Storage Cost at Steady State
- $4.34
- CloudTrail Lake Ingestion Cost
- $0.00
- Compressed Data Held
- 188.8 GB
Step by step
- 1Values used
- 2CloudTrail Storage
- 3Retention accumulation
- 4Estimated Monthly Cost= 54.34
- 5Data Event Cost= 50.00
- 6Extra Trail Copy Cost= 0.00
- 7S3 Storage Cost at Steady State= 4.34
- 8CloudTrail Lake Ingestion Cost= 0.00
- 9Compressed Data Held= 188.8 GB
Assumptions and limits
- The result is derived only from the 11 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is CloudTrail Storage calculated?
cost = data events ÷ 100,000 × event price + extra trails × management events ÷ 100,000 × copy price + compressed GB held × S3 price, plus Lake ingestion if enabled. CloudTrail gives you one free copy of management events per account, so the cost almost always comes from data events, which fire once per S3 object or Lambda invocation and can be thousands of times more numerous. Storage grows linearly until the retention window fills, so the steady-state figure is the monthly volume multiplied by the retention months, not just one month. Confirm the current data event and Lake prices for your region.
Why does CloudTrail Storage matter?
Turning on S3 data events across every bucket is the classic way to add a four-figure monthly line item overnight — scoping them to the buckets and prefixes that actually need an audit trail is what keeps CloudTrail affordable.
What values do I need to enter?
This calculator takes 11 inputs: Data events per month, Management events per month, Additional trails beyond the first, Average event record size, Retention in S3, Compressed size as a share of raw, Also ingest into CloudTrail Lake, Data event price per 100,000 events, Extra-copy management event price per 100,000, S3 storage price per GB-month, CloudTrail Lake ingestion price per GB. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Why are data events so much more expensive than management events?
Volume. Management events are control-plane calls, typically thousands a day. Data events are per object or per invocation, so a single busy bucket or a Lambda handling millions of requests generates orders of magnitude more records — and there is no free copy for them.
Should I use CloudTrail Lake or query the S3 files?
Lake charges a high per-GB ingestion fee but gives SQL over a managed, immutable store with its own retention. Querying the raw S3 JSON with Athena is far cheaper to store and lets you keep the data in your own lifecycle policy, at the cost of building the table and partitions yourself.