Estimate Artifact Registry storage from image size, retained versions and layer sharing, plus egress and scanning.
Container layers are content-addressed and stored once, so retaining ten versions of an image costs far less than ten times one image — only the changed layers add bytes. Egress, not storage, is usually the larger line once a CI system or a multi-region GKE fleet pulls the same image repeatedly from outside the registry's region. Registries grow without anyone owning them, and the two effective controls are a cleanup policy on old versions and putting the registry in the same region as the clusters that pull from it. Confirm storage, egress and scanning prices in the Google Cloud pricing calculator before budgeting.
Artifact Registry Storage
stored GB = images × size × (1 + (versions − 1) × (1 − layer sharing)); cost = (stored GB − free allotment) × storage price + pulled GB crossing a region × egress price + scans × scan price.
stored GB = images × size × (1 + (versions − 1) × (1 − layer sharing)); cost = (stored GB − free allotment) × storage price + pulled GB crossing a region × egress price + scans × scan price. Container layers are content-addressed and stored once, so retaining ten versions of an image costs far less than ten times one image — only the changed layers add bytes. Egress, not storage, is usually the larger line once a CI system or a multi-region GKE fleet pulls the same image repeatedly from outside the registry's region.
Registries grow without anyone owning them, and the two effective controls are a cleanup policy on old versions and putting the registry in the same region as the clusters that pull from it. Confirm storage, egress and scanning prices in the Google Cloud pricing calculator before budgeting.
This calculator takes 11 inputs: Distinct images, Average image size, Versions retained per image, Layers shared between versions, Storage price per GB, Free storage allotment, Image pulls per month, Pulls that cross a region or leave Google, Egress price per GB, Images scanned for vulnerabilities, Price per image scan. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Only if no other tag references the same layers. Because layers are shared, removing one version of an image frequently reclaims very little — sustained savings come from cleanup policies that retire whole generations of base images.