Understanding and Preventing Cloud Egress Bandwidth Shock
Data Transfer Out, commonly known as Egress bandwidth, is often the most misunderstood and shocking line item on a cloud bill. While inbound data transfer (Ingress) is usually free across AWS, Google Cloud (GCP), and Azure, moving data out to the internet or across regions can incur massive fees. This calculator demystifies egress costs by simulating your expected bandwidth consumption.
Common Causes of High Egress Costs
- Cross-Region Replication: Syncing databases or storage buckets across different geographic regions for disaster recovery.
- Internet Data Transfer: Serving large media files directly from S3 or EC2 without using a Content Delivery Network (CDN) like CloudFront.
- Multi-Cloud Architecture: Moving data between AWS, GCP, or on-premise data centers frequently.
The Per-GB Rate Gap Between Providers
This calculator applies default internet-egress rates of $0.09/GB (AWS CloudFront/EC2), $0.11/GB (GCP), $0.085/GB (Azure), and $0.005/GB (Cloudflare and similar modern CDNs) — the last is roughly 17–22x cheaper than the hyperscalers' list price for identical traffic out to the internet. At 50 TB/month, that gap is the difference between a bill near $4,600 on AWS and roughly $256 on Cloudflare for the exact same bytes served. These figures model direct internet egress specifically; cross-region transfer and same-region-different-AZ transfer run on separate, usually lower, rate cards that aren't reflected in this comparison.