AWS · Free tool
AWS CloudWatch Logs cost calculator
Plug in your monthly log ingest, retention, and query patterns. The calculator shows the ingestion line, the storage tail, the Logs Insights queries, and the savings from cutting retention or moving cold logs to S3. The line that surprises every team is the one with indefinite retention.
Monthly CloudWatch Logs bill
Total / month
$0
Ingestion
$0
Storage tail
$0
Logs Insights
$0
Annualized
$0
12 months at this rate.
Retention savings scenarios
- Adjust retention above to see scenarios.
If your bill is bigger than expected, check these
- VPC Flow Logs in full mode logging accept+reject. Switch to reject-only or sample at 10% to cut Flow Log ingest 90%.
- Log groups with no retention (the default). Apply 14 or 30 days to everything that does not need history.
- Lambda functions writing console.log on every invocation. Move to debug-only logging in prod.
- CloudFront real-time logs sent to CloudWatch instead of Kinesis Firehose to S3. Firehose+S3 is 80% cheaper for the same data.
Why CloudWatch Logs grows quietly
New log groups default to indefinite retention. Every log group
created via the console, the SDK, or a Terraform module that did
not set retention_in_days is silently keeping its
data forever. Storage at $0.03 per GB per month feels cheap until
you have 10 TB of two-year-old logs that no one queries.
VPC Flow Logs in full mode log every accepted and rejected packet. A medium VPC with 50 active EC2 instances generates 1 to 3 TB of Flow Logs per month at $0.25 per GB ingest. That is $250 to $750 per month for data most teams query under a dozen times per quarter.
The fix is rarely a tooling project. It is reading
aws logs describe-log-groups sorted by stored bytes,
identifying the long tail with no retention, and applying 14 or
30 days. The next month the bill drops by half.
Run this on your real account
Free 14-day audit, read-only IAM role, one-page CFO summary.
We pull every log group, sort by stored bytes, identify the no-retention long tail, and hand the engineer the exact retention policy to apply. The audit is free, the report is yours, no upsell call.
Frequently asked
Why is CloudWatch Logs so expensive?
Three lines stack on top of each other. Ingestion at $0.50 per GB is the biggest one and surprises every team running VPC Flow Logs in full mode (every accepted and rejected packet logged). Storage at $0.03 per GB per month sounds cheap but most log groups have indefinite retention by default and accumulate forever. Logs Insights queries at $0.005 per GB scanned are usually small but can spike if anyone runs analytics queries against multi-TB groups.
What is the default retention for a new log group?
Never expire. AWS does not set a retention policy on new log groups. Every team that creates a log group from the console or SDK without explicitly setting retention is silently committing to keeping that data forever and paying $0.03 per GB per month indefinitely. The single highest-leverage change in most accounts is to apply a 14- or 30-day retention to every log group that does not need long history.
Can I export old logs to S3 and stop paying CloudWatch storage?
Yes. CloudWatch Logs supports an export-to-S3 task that writes log events as compressed objects. S3 Standard at $0.023 per GB or S3 Glacier Instant Retrieval at $0.004 per GB is much cheaper than CloudWatch Logs storage at $0.03 per GB. The trade-off is that you lose Logs Insights querying. For audit-grade retention where the logs are rarely queried, the export pattern saves 87 percent.
How do I find the log groups driving the bill?
AWS does not show per-log-group cost on the bill. The Cost and Usage Report has aggregated CloudWatch Logs lines by region and usage type but does not split by log group. To attribute, run aws logs describe-log-groups and sort by storedBytes. The top 5 log groups usually account for 80 percent of the bill. The largest one is almost always /aws/vpc/flowlogs in accounts that enabled Flow Logs in full mode.
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