AWS to Azure data transfer cost
AWS to Azure costs AWS internet egress ($0.09/GB first 10 TB). Azure ingress is free. Reverse direction: Azure Zone 1 egress is $0.087/GB first 5 TB. Azure tier breaks are at 5 TB / 10 TB / 150 TB whereas AWS breaks at 10 TB / 50 TB / 150 TB, so cost-per-volume comparison depends on size.
Both directions, per volume
| Volume | AWS to Azure | Azure to AWS | Cheaper direction |
|---|---|---|---|
| 1 TB | $83.70 | $87.00 | AWS to Azure |
| 10 TB | $911.36 | $887.10 | Azure to AWS |
| 50 TB | $4,402.94 | $3,549.10 | Azure to AWS (-19%) |
| 100 TB | $8,072.94 | $7,141.10 | Azure to AWS (-12%) |
| 1 PB | $54,122.94 | $52,621.10 | Azure to AWS (-3%) |
Numbers exclude NAT Gateway charges (AWS side) or ExpressRoute (Azure side). For per-byte API charges, both clouds free of API-call fees in the typical S3 / Blob transfer.
Where the asymmetry comes from
Azure has a single 5 TB first tier at $0.087/GB. AWS keeps you on the $0.09/GB rate for the first 10 TB. For small workloads (under 5 TB), AWS-out is slightly cheaper because the small absolute volume hides the per-GB difference. From 10 TB upwards, Azure's faster tier drop ($0.083/GB after 5 TB, $0.07/GB after 10 TB) overtakes AWS's slower tier drop.
Operational note: Azure ingress from AWS often shows up in Azure Cost Management as "data in" with zero cost. The Azure side will not warn you about the AWS-side egress bill. You only see it on your AWS invoice. For multi-cloud workloads, build a script that joins both bills weekly so you do not get surprised.
See also: AWS to GCP transfer, Multi-cloud replication math.