CloudFront logs cost: estimate storage, retention, and queries

CloudFront log costs rarely show up as a single “CloudFront fee”. They usually appear as S3 storage, analytics scans, and SIEM/log platform ingestion. Estimate them like any other log pipeline: ingestion, retention, and query/scan.

CloudFront log cost inputs

• Log lines: requests/month x log lines per request.
• Log size: avg KB per line to get GB/month ingestion.
• Retention: days kept drives storage baseline.

Step 0: know which log stream you enabled

• Standard access logs: delivered to an S3 bucket; your costs are mostly S3 + analytics on top.
• Real-time logs: delivered to a real-time destination (often a stream); costs depend on the pipeline you choose.

If you forward logs into another platform (CloudWatch Logs, Datadog, Splunk, etc.), include that platform’s ingestion and retention pricing as well.

1) Estimate log ingestion (GB/day)

A rough model starts from request volume: standard access logs are “about one record per request”. The missing variable is bytes per log line, which depends on fields and header lengths.

• requests/day × bytes/log ~= bytes/day
• bytes/day / 1e9 ~= GB/day

Related: estimate log ingestion (GB/day).

2) Convert retention into GB-month (storage baseline)

Steady-state model: retained GB ~= ingestion GB/day × retention days.

Guide: log retention storage cost.

3) Add query/scan costs (often dominates)

• Frequency: dashboards, scheduled jobs, incident response searches
• Scan size: GB scanned per query (filters and partitions change this dramatically)
• Downstream joins: combining CDN logs with app logs and WAF logs increases scan volume

Tool: log search scan cost.

Cost control levers (keep visibility)

• Retention tiers: short retention for raw logs; longer retention for aggregated/security signals.
• Partition well: store logs by date prefix so queries scan days, not months.
• Avoid repeated broad scans: use targeted queries and dashboards that don’t scan “all time”.
• Route selectively: forward only high-value subsets (errors, specific paths, security events) into expensive tooling.

Validation checklist

• Measure actual log GB/day from the destination (S3, CloudWatch, SIEM) for a representative week.
• Confirm retention settings and lifecycle policies (including any replicated copies).
• Measure query scan GB for your real dashboards and incident playbooks.

Related links

Sources

• CloudFront logging: docs.aws.amazon.com
• S3 pricing (common storage destination): aws.amazon.com/s3/pricing
• Athena pricing (common query engine): aws.amazon.com/athena/pricing

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