Egress Cost Guide (cloud data transfer pricing)

Egress is the data your cloud sends out (including AWS egress cost). For many products, egress is the "silent" line item that grows with usage. This guide helps you estimate egress quickly, pick the right unit, and avoid common double-counting traps.

1) Identify what kind of transfer you have

Internet egress: data leaving your provider to end users.
Cross-region transfer: replication, multi-region reads, DR traffic.
CDN bandwidth: edge delivery (may be priced separately from origin egress).
Cross-AZ transfer: east-west traffic across Availability Zones (often a surprise).

2) Pick the right unit (GB vs GiB)

Billing is often in decimal GB/TB, while OS tools might show GiB/TiB. Convert before estimating costs. Use the Units Converter if you're unsure.

3) Estimate GB per month (quick methods)

From billing/metrics: use measured bytes sent or transfer GB in billing exports.
From API volume: requests/day x average response KB -> GB/month (use API response transfer).
From throughput: Mbps x utilization x time -> GB/month (use Units Converter).

4) Model cost with simple assumptions first

Start with "GB/month x $/GB". You can refine later for tiering and free allowances. Tools: Egress, CDN bandwidth, cross-region transfer.

5) Validate (avoid double counting)

Separate CDN edge bandwidth from origin egress (cache fill).
Separate cross-AZ from internet egress (they are different boundaries).
Re-check during incident windows: retries/timeouts can multiply traffic and create spikes.

Common pitfalls

Tiered pricing: your average $/GB changes as traffic grows.
Double counting: CDN bandwidth may not equal origin egress.
Replication direction: some services bill only outbound, others have nuances.
Cross-AZ traffic: load balancers and multi-AZ clients can create steady east-west transfer.

More egress guides

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A practical cost comparison of API Gateway, Application Load Balancer (ALB), and CloudFront. Compare request pricing, data transfer, caching impact, WAF, logs, and the hidden line items that change the answer.

Artifact Registry pricing (GCP): storage + downloads + egress (practical estimate)

A practical Artifact Registry cost model: stored GB-month baseline, download volume from CI/CD and cluster churn, and outbound transfer. Includes a workflow to estimate GB-month from retention and validate layer sharing and peak pull storms.

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A practical AWS cost checklist for planning and reviews: define scope, identify top cost drivers (requests, GB, GB-month, hours), and avoid the common blind spots (data transfer, logs, and cross-AZ).

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A practical guide to AWS cross-AZ data transfer costs: common causes (load balancers, databases, Kubernetes), how to estimate GB crossing zones, and how to reduce it safely.

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AWS network cost guide: NAT, VPC endpoints, PrivateLink, and data transfer (what to model)

A practical AWS network cost hub: how to model NAT Gateway, VPC endpoints/PrivateLink, and cross-AZ/cross-region data transfer. Includes formulas, break-even workflow, and a troubleshooting checklist.

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A practical PrivateLink pricing checklist: interface endpoint-hours, per-GB processing, and provider-side considerations. Includes the transfer pitfalls that cause surprise bills.

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A practical guide to AWS VPC data transfer costs: where transfer happens in real architectures, how to estimate GB/month, and how to avoid surprises.

Azure API Management pricing: model requests, transfer, and log volume

A practical API Management estimate: request volume, response transfer, and logs/observability. Includes a checklist to validate retries, payload size, and usage tiers.

Azure bandwidth and egress costs: how to estimate outbound data transfer

A practical method to estimate outbound bandwidth costs: split by destination (internet, cross-region, CDN origin), validate units, and avoid double-counting.

A practical guide to network transfer costs: how to model internet egress, cross-region transfer, cross-AZ traffic, and CDN cache fill. Includes estimation steps and validation tips.

AWS network cost guide: NAT, VPC endpoints, PrivateLink, and data transfer (what to model)

AWS VPC data transfer cost: estimate cross-AZ, cross-region, and egress

A practical guide to AWS VPC data transfer costs: where transfer happens in real architectures, how to estimate GB/month, and how to avoid surprises.

Azure bandwidth and egress costs: how to estimate outbound data transfer

A practical method to estimate outbound bandwidth costs: split by destination (internet, cross-region, CDN origin), validate units, and avoid double-counting.

S3 data transfer costs: egress, cross-region access, and common surprises

A practical guide to S3 data transfer costs: what counts as egress, how cross-region access shows up on bills, and how to estimate GB/month from your traffic patterns.

AWS cross-AZ data transfer cost: causes and estimate steps

A practical guide to AWS cross-AZ data transfer costs: common causes (load balancers, databases, Kubernetes), how to estimate GB crossing zones, and how to reduce it safely.

Related calculators

Data Egress Cost Calculator

Estimate monthly egress spend from GB transferred and $/GB pricing.

API Response Size Transfer Calculator

Estimate monthly transfer from request volume and average response size.

VPC Data Transfer Cost Calculator

Estimate data transfer spend from GB/month and $/GB assumptions.

Cross-region Transfer Cost Calculator

Estimate monthly cross-region transfer cost from GB transferred and $/GB pricing.

FAQ

What counts as egress?

Any data leaving a billing boundary: internet egress to users, cross-region transfers, and sometimes cross-AZ traffic depending on the service and architecture.

Why do egress bills spike?

Because egress scales with traffic. Common causes are CDN cache miss/origin egress, cross-AZ chatty microservices, replication, and retries/timeouts during incidents.

How do I estimate GB/month quickly?

Use one of three methods: (1) measured bytes from billing/metrics, (2) throughput (Mbps) to GB/month, or (3) requests/day x average response size to GB/month.

Does CDN bandwidth equal origin egress?

Not necessarily. CDN bandwidth is edge-to-user delivery. Origin egress (cache fill) is origin-to-CDN traffic and is often billed separately by the origin provider.

Last updated: 2026-02-23