Cloud data egress is data leaving a cloud provider's infrastructure for another destination. Uploading a file into the cloud is ingress; a recipient downloading that file to an office, home workstation, another cloud, or an on-premises system is egress. Providers often make internet ingress free and meter internet egress by the amount transferred.
Think of storage as warehouse rent and egress as outbound delivery. The analogy is imperfect, but it explains why one stored file can create repeated charges: the provider stores one copy, yet each recipient download sends another set of bytes across a network boundary.
Follow one file through its lifecycle
Suppose a producer uploads a 500 GB package into object storage.
- Upload: The 500 GB enters the provider. Azure and Google Cloud list inbound internet transfer as free, but storage capacity and write operations can still be charged.
- Storage: The package occupies capacity for its retention window. The rate depends on region, storage class, and redundancy.
- Retrieval: If the package sits in a lower-cost access tier, reading it can create a separate per-GB retrieval charge.
- Delivery: When a recipient downloads 500 GB over the internet, those bytes leave the provider and may be billed as egress.
- Redelivery: If ten recipients each download the complete package, the provider sends 5,000 GB. The object was stored once but delivered ten times.
- Deletion: Capacity billing stops when deletion takes effect, although a minimum-retention or early-deletion charge may still apply to some colder tiers.
That sequence is why “How large is the file?” is only the first billing question. You also need to ask how long it remains, how often it is read, where it goes, and whether the provider counts decimal GB or binary GiB.
A simple dated example
Azure's USD public list page, accessed August 10, 2026, shows the first 100 GB per month of internet data transfer out free. On the premium Microsoft global network, the next 10 TB from North America or Europe is listed at $0.087/GB.
Under those assumptions, downloading 500 decimal GB once would use the 100 GB allowance and leave 400 GB billed:
400 GB × $0.087/GB = $34.80
If ten recipients each downloaded all 500 GB in the same month, total egress would be 5,000 GB:
(5,000 GB - 100 GB) × $0.087/GB = $426.30
These calculations assume the allowance was otherwise unused, the traffic used premium-network internet routing from North America/Europe, and all paid bytes remained in the first band. They exclude storage, retrieval, operations, CDN, taxes, contracts, and discounts. They are illustrative list-price examples, not quotes, TeraAirlift prices, or actual TeraAirlift economics.
Not every movement is the same kind of egress
Cloud invoices separate paths because the underlying network path differs:
- movement within one zone or service boundary may be free or separately priced;
- movement between regions can use an inter-region meter;
- internet delivery is usually tiered by source geography, destination, routing, and volume;
- CDN delivery can substitute CDN request and transfer pricing for some origin traffic;
- private connectivity and acceleration products have their own charges.
Azure's August 10, 2026 list page, for example, displayed first paid premium-network internet bands of $0.087/GB from North America/Europe, $0.12/GB from Asia/Australia/Middle East and Africa, and $0.181/GB from South America. That does not mean every outbound Azure byte receives one of those prices. It means location and route belong in the estimate.
Retrieval is not egress
Retrieval is the storage service making data in a lower-cost tier available to read. Egress is the network carrying the data outward. A single download can incur both.
For East US pay-as-you-go LRS examples in the Azure Retail Prices API accessed August 10, 2026, Cool retrieval was listed at $0.01/GB and Cold retrieval at $0.03/GB. Internet bandwidth could then be charged separately. Archive data must first be rehydrated, and Microsoft says standard-priority rehydration may take up to 15 hours for objects under 10 GB. Tier, region, object size, priority, and current demand matter.
Operations are separate again. Writing blocks, reading blocks, listing objects, or making API requests can carry transaction charges even when ingress bandwidth is free.
Free allowances and exit programs have boundaries
AWS documents 100 GB per month of internet data transfer out free when aggregated across eligible AWS services and regions outside China and GovCloud. Google Cloud's Always Free terms include 100 GB per month from North America to eligible destinations. The scopes are not interchangeable.
AWS, Azure, and Google also describe programs for eligible customers moving data off their platforms. These are provider-exit or switching processes with conditions, notices, support requests, or agreement consequences. They do not make normal day-to-day internet delivery free.
The EU Data Act applies from September 12, 2025 and phases out defined, in-scope switching charges from January 12, 2027, subject to its scope and exceptions. That legal concept is not the same as ordinary egress while continuing to use a service. This is educational context, not legal advice; obtain qualified advice for a particular contract or migration.
Questions to ask before estimating egress
- What service, source region, and storage class hold the data?
- Is the destination the internet, another region, another cloud, or on-premises?
- How many complete and partial downloads are expected?
- Which monthly allowance and volume band apply?
- Are retrieval, operations, replication, or early deletion charged separately?
- Does the price use GB, GiB, TB, or TiB?
- Are taxes, currency conversion, enterprise agreements, or CDN charges involved?
For the cost consequence, see why egress can exceed storage. To estimate upload plus recipient-download time, use the transfer-time calculator.
Where TeraAirlift fits
TeraAirlift is a Windows-first desktop operations console for large-file delivery with recipient controls, short-lived storage access, and SHA-256 integrity verification. Plans start with a 10 TB included allotment, not a minimum package size; volume above the allotment is overage. Final rates, metering details, retention, and billing design remain under evaluation, so this article should not be read as a TeraAirlift price sheet.
Sources
- Azure Bandwidth pricing — inbound, internet egress, routing, geography, and free allowance; accessed August 10, 2026.
- Azure Retail Prices API — Storage in East US — retrieval and operation examples; accessed August 10, 2026.
- Azure Blob access tiers — tier behavior and minimum retention.
- Google Cloud Storage pricing — inbound transfer, egress, and eligible allowance; accessed August 10, 2026.
- Amazon S3 pricing — eligible 100 GB aggregate allowance and egress qualifications; accessed August 10, 2026.
- Regulation (EU) 2023/2854 — Data Act switching definitions and timeline.
