Container registry cost compared: ECR vs ACR vs Artifact Registry

Quick answer

AWS ECR and GCP Artifact Registry price per GB stored (~$0.10/GB-month) plus egress, so cost scales with registry size and cross-region/internet pulls. Azure ACR uses a flat daily tier fee (Basic ~$5, Standard ~$20, Premium ~$50/month) that bundles storage and throughput. The cheapest depends on size and pulls: per-GB (ECR/Artifact Registry) suits small registries, ACR's flat tier suits predictable larger ones. All share the same lever: keep pulls in-region and prune old images.

Container registries store and serve your images, and the three major clouds price them in two shapes: AWS ECR and GCP Artifact Registry are usage-based (per GB plus egress), while Azure ACR uses a flat tiered daily fee. All are inexpensive, and the shared optimizations, keeping pulls in-region and pruning images, apply to all.

Two pricing shapes

Registry	Model
AWS ECR	~$0.10/GB-month storage + egress; in-region pulls to AWS compute free
GCP Artifact Registry	~$0.10/GB-month storage + egress; in-region pulls cheap
Azure ACR	Flat daily tier (Basic/Standard/Premium) bundling storage + throughput

ECR and Artifact Registry charge per gigabyte stored (about $0.10/GB-month) plus egress, with in-region pulls to same-cloud compute cheap or free, as in ECR and Artifact Registry. ACR uses a flat daily tier fee that bundles storage and throughput, as in ACR. So ECR/Artifact Registry cost scales with size, while ACR is predictable by tier.

Which is cheaper

For a small registry, the per-GB model (ECR, Artifact Registry) can be cheaper than ACR's minimum tier fee. For a larger registry, ACR's flat tier can be cheaper and more predictable than per-GB storage. All three are cheap in absolute terms, so the difference is small; the pull topology (egress) usually matters more than the storage model.

The shared levers

On all three, keep pulls in-region to same-cloud compute (cheap or free) rather than cross-region or to the internet (billed egress), cache base layers in CI so builds do not re-pull, and prune old and untagged images with lifecycle/cleanup policies so storage (or the need for a higher ACR tier) stays flat. Geo-replication multiplies storage on all three, so replicate only necessary regions.

Choosing on cost

Use the registry on the cloud where your compute runs (for cheap in-region pulls and to avoid cross-cloud egress), and on any of them keep pulls local and prune images. The storage-model difference (per-GB versus flat tier) is minor; ecosystem fit and pull topology dominate, the same choose-by-ecosystem conclusion as other cross-cloud comparisons.

FAQ

Is ECR, ACR, or Artifact Registry cheapest?

It depends on registry size and pull topology. ECR and Artifact Registry charge per GB stored plus egress, cheaper for small registries. ACR's flat daily tier fee can be cheaper and more predictable for larger registries. All are inexpensive; the pull topology (egress) usually matters more than the storage model. Use the registry on your compute's cloud.

How do container registry pricing models differ?

AWS ECR and GCP Artifact Registry are usage-based, charging per GB stored (about $0.10/GB-month) plus egress, with in-region pulls to same-cloud compute cheap or free. Azure ACR uses a flat daily tier fee (Basic, Standard, Premium) that bundles storage and throughput. So ECR/Artifact Registry scale with size while ACR is predictable by tier.

What are the shared container registry cost levers?

Keep pulls in-region to same-cloud compute (cheap or free) rather than cross-region or internet (billed egress), cache base layers in CI so builds do not re-pull, prune old and untagged images with cleanup policies, and geo-replicate only necessary regions. These apply identically to ECR, ACR, and Artifact Registry.

Does storage or egress drive container registry cost?

Usually egress and pull topology more than storage, since storage is cheap (about $0.10/GB-month or bundled in ACR's tier) and images are modest. Cross-region and internet pulls incur egress, while in-region pulls to same-cloud compute are cheap or free. Keeping pulls local is the highest-impact lever across all three.

Should I choose a cloud based on container registry cost?

No. The registries are all inexpensive with small differences, so use the one on the cloud where your compute runs, for cheap in-region pulls and to avoid cross-cloud egress. Ecosystem fit and pull topology dominate; the storage-model difference (per-GB versus flat tier) is minor.

Does C3X estimate container registry cost?

C3X prices ECR, ACR, and Artifact Registry from your Terraform, including per-GB storage and ACR's tier fee, so the fixed components appear before deploy. Egress depends on pull volume and topology, which you provide as usage assumptions.

What to do next

Compare registries for your workload. C3X reads your Terraform and prices your resources against a live catalog. Start with the quickstart.