Cloud egress costs explained

Cloud providers may charge when data leaves their services. This charge, called egress, covers data sent to users, transferred between regions, or moved to another provider during a migration.

Rates depend on where the data starts and ends. They also depend on how much moves and which network services carry it. Before comparing cloud costs or planning a migration, check the route and estimate the traffic.

What counts as egress

Ingress is data coming into a cloud; egress is data leaving it. Providers often make incoming transfers free while charging for outgoing ones, but the rules depend on the service and route.

When a service sends a video to a viewer, that transfer counts as egress. So does a company copying data to another cloud. Prices can differ by route: transfers between cloud regions may cost differently from transfers to the public internet or over a dedicated connection. Services that help move the data, such as a load balancer or a network address translation service, can add charges too.

What affects egress rates

Providers base rates partly on the region where the data starts and its destination. The network route and amount transferred each month also affect the rate. Some providers offer a free allowance, then charge for each unit of data. Higher usage can qualify for lower rates per unit.

The units matter. A gigabyte (GB) and a gibibyte (GiB) are different units. A quote priced per GiB will not match a per-GB quote exactly, even before accounting for other differences.

Cloud egress price examples

A list price alone doesn’t tell you which provider will cost less. The examples below show prices for traffic sent to the internet. The examples use different routes and units. Their free allowances and other pricing details also vary.

For example, sending about 1,000 GB to the internet in a month would cost around $81 on AWS if the 100 GB allowance applies and the remaining 900 GB falls in the first paid tier. The comparable Azure example comes to about $78.30 using the North America or Europe Premium Global Network rate. For Google Cloud, 1,000 GB is roughly 931 GiB; at the listed North America Premium Tier rate, the result is about $112 after the first free GiB.

These examples illustrate list prices; they do not estimate a bill. They leave out other network and processing charges, taxes, negotiated rates, and account-specific terms. Google’s example uses GiB, while the AWS and Azure examples use GB. Google also offers a Standard Tier that costs less than Premium Tier but uses the public internet for the route between services and users. Check the relevant provider calculator and the exact route for a workload estimate.

Why egress costs matter

A service that regularly sends large amounts of data to users or another region can generate recurring charges. A one-time migration can also produce a large bill if it moves a lot of data. Estimate how much data you send and read over time, not just how much you store.

Egress can also make switching providers or running across multiple clouds more expensive. The European Commission identifies high egress charges as a potential barrier to switching. At the same time, the U.S. Government Accountability Office reported in 2023 that Department of Defense officials did not consider egress fees a primary cause of vendor lock-in in their experience. Those officials said the fees represented less than 1% of known Department of Defense cloud expenditures, but the department lacked a capability to track and report the fees across the organization. That figure reflects the department’s reported experience and should not be treated as typical of cloud customers overall.

Providers have offered their own rationale for charging: AWS says its data-transfer pricing reflects investment in network equipment and backbone infrastructure. That explains AWS’s position, but it does not show what any particular transfer rate costs the provider. Egress is one cost and one possible barrier to switching, alongside factors such as provider-specific services and the skills needed to operate them.

How to estimate your bill

Start with a traffic estimate: how many gigabytes leave the service each month, and where do they go? Then identify the source and destination regions and the route. Note any services that handle the traffic. Check whether a free allowance applies and how the provider aggregates it. Also confirm whether the listed rate uses GB or GiB.

Include related charges in the comparison. A content delivery network serves file copies from locations closer to users. It can charge for delivery and for filling its cache with those copies. Network services that process or route traffic can also add fees. Compare the full workload cost rather than treating the headline egress rate as the total.

If you are planning a migration, check for provider credits or transfer programs before budgeting around them. AWS and Azure have published programs for eligible customers moving away, but eligibility and request procedures apply. These programs do not make ordinary ongoing internet traffic free.

EU switching charges

The EU Data Act sets a schedule for charges associated with switching data-processing services. Under the European Commission’s published schedule, providers may charge switching and egress costs during the transition period from January 11, 2024, through January 11, 2027. Switching charges are to be removed starting January 12, 2027.

That rule concerns switching charges. It does not mean all ordinary data transfers will become free. Dutch regulator guidance distinguishes fees for switching from charges for actual transfers when a customer uses cloud providers in parallel; those transfer costs may still apply. Check the contract and the specific transfer before assuming a fee is covered by the rule.