Registry Storage Calculator

Work out registry storage instantly with clear inputs, formula shown and shareable results.

About Registry Storage Calculator

Registries store layers by content digest, so a shared base image is stored once no matter how many tags reference it. Storage therefore grows with unique layer data per push, not with total image size — which is why 5,400 retained images can occupy far less than their nominal sum, and why changing the base image is the event that suddenly doubles registry usage.

Formula

Registry storage

unique data = images per day x new layer MB x retention days; total = unique + shared base; naive = images x (unique + base)

Worked example

With the default values below, Registry Storage Calculator returns Registry storage required of 226.59 GiB. Change any input above and every figure here is recalculated in your browser.

Inputs used

Images pushed per dayminimum 1: 60
New unique layer data per imageminimum 0.1 MB: 45 MB
Tag retentionminimum 1 days: 90 days
Shared base image sizeminimum 0 MB: 300 MB

Results

Registry storage required: 226.59 GiB
Storage saved by layer sharing: 1.47 TiB
Image tags retained: 5,400
Deduplication ratio: 7.66 x

Step by step

1Values used
2Registry storage
3Registry storage required= 243,300,000,000
4Storage saved by layer sharing= 1,619,700,000,000
5Image tags retained= 5,400
6Deduplication ratio= 7.66 x

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What makes registry storage grow unexpectedly?

Base image changes, since a new base digest means no sharing with existing tags. Also multi-architecture builds, which multiply layers per tag.

Should untagged manifests be deleted?

Yes. Untagged images from overwritten tags keep their layers alive. Garbage collection of untagged manifests is usually the largest single reclaim available.