AWS vs Azure vs GCP cost: why no cloud is universally cheapest

Quick answer

No cloud is universally cheapest — comparable compute and storage sit in a narrow band across AWS, Azure, and GCP. The real differences are egress pricing, the discounts you'll actually commit to, and which managed services your workload needs. Compare equivalent resource shapes with realistic discounts applied, not list prices — and don't go multi-cloud expecting savings; the egress and complexity usually outweigh it.

"Which cloud is cheapest" is the wrong question. For the bread- and-butter resources — a VM with N vCPUs and M GB of RAM, a terabyte of SSD, a managed Postgres instance — AWS, Azure, and GCP land remarkably close. The cost differences that actually move a bill live in three places, and a fair comparison has to account for all of them.

1. Egress is the real differentiator

Compute and block storage are close across providers; data transfer out is where pricing and free allowances diverge meaningfully. For content- heavy, data-pipeline, or API-heavy workloads, egress can dominate the bill — so model it explicitly using each provider's rates. See AWS data transfer and GCP egress for how different the structures are.

2. Discounts decide the real price

Most production spend isn't on-demand. Compare the discount each cloud offers for your commitment appetite:

AWS — Reserved Instances vs Savings Plans
Azure — Reservations vs Savings Plans, plus Hybrid Benefit
GCP — Committed Use vs Sustained Use

Comparing list prices while ignoring these is how teams reach the wrong conclusion.

3. Managed services break the symmetry

The closer you get to managed/serverless services, the more the pricing models diverge — and the more lock-in matters. A workload built on BigQuery, Cosmos DB, or Aurora is priced on that service's terms, not a generic VM rate. Compare the specific services your architecture uses, not just raw compute.

Should you go multi-cloud for cost?

Almost never. Splitting workloads across clouds adds inter-cloud egress, duplicated tooling, and operational overhead that typically exceeds any price arbitrage. Go multi-cloud for resilience, data residency, or a best-of-breed service — and budget the cost as a tax, not a saving.

FAQ

Is AWS, Azure, or GCP cheapest?

For comparable compute and storage, the three are within a narrow band — no provider is universally cheapest. The differences that matter are egress pricing, the discount programs you'll actually use (Reserved Instances, Savings Plans, Committed Use, Hybrid Benefit), and which managed services your workload depends on. The cheapest cloud is the one whose pricing model fits your specific workload.

How do I compare cloud costs apples-to-apples?

Match real resource shapes, not list prices: equivalent VM sizes (vCPU + RAM), equivalent storage classes and IOPS, and the same data-transfer assumptions. Include the discount you'd realistically commit to on each. Comparing on-demand list prices alone is misleading because most production spend is discounted.

What's the biggest cost difference between clouds?

Egress (data transfer out). Pricing and free allowances differ meaningfully across providers, and for content- or data-heavy workloads egress can dominate the bill. Compute and block storage are close; egress and a few premium managed services are where the gaps open up.

Should I go multi-cloud to save money?

Rarely for cost alone. Multi-cloud adds egress between clouds, duplicated tooling, and operational complexity that usually outweighs price arbitrage. Multi-cloud makes sense for resilience, data residency, or using a best-of-breed service — but treat the cost as a tax to manage, not a saving.

How do I estimate costs across all three clouds?

Use a tool that prices AWS, Azure, and GCP resources from the same definitions. C3X estimates Terraform across all three providers against a live pricing catalog, so you can put equivalent architectures side by side before committing to a cloud.

Does C3X support all three major clouds?

Yes. C3X prices AWS, Azure, and Google Cloud resources from a single catalog (1,300+ resource types), so a multi-cloud or migration cost comparison runs from one tool rather than three separate calculators.

What to do next

A fair comparison needs equivalent architectures priced consistently. C3X estimates AWS, Azure, and GCP resources from one catalog, so you can put the same workload on each cloud and compare with realistic numbers rather than marketing rates. The quickstart runs it on your Terraform in minutes.