Egress Cost
The cost charged by cloud providers for data transferred out of their S3 service — to the internet, another region, or another cloud.
Summary
The cost charged by cloud providers for data transferred out of their S3 service — to the internet, another region, or another cloud.
Egress cost is the economic force that shapes S3 architecture decisions. It discourages multi-cloud, encourages co-located compute, and makes data gravity a real constraint.
- Egress is not just internet-bound traffic. Cross-region, cross-AZ, and VPC endpoint transfers all have cost implications, though the rates differ.
- Egress costs can represent 25-35% of total cloud spend for data-heavy workloads. Budget for it explicitly, not as a surprise.
- AWS S3
constrained_byEgress Cost — cloud data transfer charges - Local Inference Stack
solvesEgress Cost — keeps data and compute co-located - Tiered Storage
solvesEgress Cost — cold data stays cheap, hot data stays close - Separation of Storage and Compute
constrained_byEgress Cost — data must travel to compute scoped_toS3, Object Storage
Definition
The cost charged by cloud providers for data transferred out of their S3 service, whether to the internet, another region, or another cloud.
Recent developments
- AWS internet egress: $0.09/GB for first 10 TB; tier drops to $0.05/GB above 150 TB. Tiered pricing structure: $0.09/GB first 10TB, $0.085/GB next 40TB, $0.07/GB next 100TB, $0.05/GB above 150TB. First 100 GB/month is free across all regions + services. Per EgressCost.com — AWS Data Transfer 2026.
- Cross-region typically $0.02/GB, dropping to $0.01-0.015/GB on intra-continent corridors. Inter-continent cross-region transfers are more expensive than intra-continent (e.g. us-east-1 → us-west-2 is $0.02/GB). Per LeanOps — AWS Data Transfer Pricing 2026.
- Cross-AZ + NAT Gateway compound the cost. Cross-AZ transfer charges $0.01/GB each way; cross-region adds $0.01-0.02/GB; NAT Gateway processing adds $0.045/GB on top. The compounding makes naively-architected multi-AZ + multi-region apps surprisingly expensive. Per Stormit — AWS Data Transfer Pricing.
- CloudFront-to-S3 same-account = free egress. AWS does not charge data transfer from S3 to CloudFront when both are in the same account — deliberate incentive to use CloudFront for content delivery. Per CloudZero — AWS Egress Costs.
- "Your S3 bill is 2-3× the pricing page." Per LeanOps's 2026 cost-audit analysis, the gap between the published S3 pricing page and the actual bill operators see is consistently 2-3× because egress + cross-AZ + cross-region + request fees aren't in the headline storage rate. Per LeanOps — Why Your S3 Bill Is 2-3x.
Connections 27
Outbound 2
scoped_to2Inbound 25
constrained_by2solves22Resources 3
Official AWS Architecture Blog comprehensively documenting data transfer costs across common architectures, including internet egress, cross-AZ, cross-region, and VPC endpoint scenarios.
Official AWS documentation explaining data transfer charge line items in Cost and Usage Reports, the authoritative reference for understanding egress billing.
Detailed explanation of all AWS data transfer cost categories and how egress can represent 25-35% of total cloud spend for data-heavy platforms.