AWS bill line item
DataTransfer-Out-Bytes
You are being charged per gigabyte for data leaving an AWS region to the public internet.
Internet data transfer out
Verified against official AWS documentation last checked
Why it shows up
This is the single most common line item on almost every AWS bill: any response an EC2 instance, load balancer, or API sends back to a browser, mobile app, or external API counts as egress. It often appears bundled under "EC2-Other" in Cost Explorer even when the traffic originated from another service that routes through EC2-managed infrastructure.
Spikes usually trace to a new public-facing feature (video/image delivery, large API payloads, backups pushed to an external destination), a bot or scraping wave hitting an unprotected endpoint, or serving large static assets directly instead of through a CDN.
How to cut it
- Put CloudFront (or another CDN) in front of anything served repeatedly to the public internet. CDN egress pricing is lower than direct-to-internet, and cached hits avoid origin egress entirely.
- Compress payloads (gzip/brotli) and move large downloadable files to S3 with appropriate storage/lifecycle tiers rather than serving from compute instances.
- Check for unintended public exposure (an open bucket, an unauthenticated endpoint) if the increase isn't tied to a known feature launch.
- Track usage against the account-wide free-tier allotment and the volume tiers below it so pricing assumptions match the actual tier.
$0.09 per GB (first 10 TB/month tier) — us-east-1, applies after the AWS-wide free tier; as of 2026-07
How to read a usage type
DataTransfer-Out-Bytes carries no region or direction token, so there's nothing to break down here.
Source
Source: AWS docs →Found DataTransfer-Out-Bytes on your own bill?
Drop your Cost Explorer CSV into the AWS Bill Analyzer. It'll flag line items like this one on your own bill and link straight back to the fix.
Analyze your own bill →The meter you don't watch still grows.
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