Cloud Storage Cost Calculator

Cloud storage bills have two moving parts in this calculator: what you keep and what you pull back out. Storing 1,000 GB at 0.02 per GB costs 20 a month. Reading that same 1,000 GB back out at 0.08 per GB costs 80, four times the storage charge, for a single full retrieval.

Per-GB rates differ by provider, region and storage class, so the figures here are whatever you enter rather than any provider's list price. Current rate cards are published by Amazon S3 and Google Cloud Storage, and both separate the storage line from the data-transfer-out line in the same way this calculator does.

Egress pricing has drawn regulatory attention as a barrier to moving between providers. The EU Data Act requires providers to withdraw the charges levied on a switching process, and states that standard service fees for the service itself are not switching charges, which is where ordinary transfer-out billing sits. The asymmetry in everyday transfer pricing is worth modelling whatever the regulation reaches.

Run it with sensible defaults

Storage of 1,000 GB at 0.02 per GB, plus 100 GB of egress at 0.08 per GB, gives 20 of storage and 8 of egress: 28.00 a month and 336.00 a year, with egress at 28.57% of the bill. The defaults are a starting point rather than a suggestion.

The levers in this calculation

All four inputs move the monthly total, in two pairs. A 1% rise in stored volume or in the storage rate moves it by 0.71%; a 1% rise in egress volume or in the egress rate moves it by 0.29%. Volume and rate are interchangeable inside each pair, because each term is just one multiplied by the other.

The split is not fixed. It is each component's share of the bill, so it moves with your own numbers: at the worked example below, 5,000 GB stored against 800 GB pulled out, storage falls to 48.39% of the bill and egress rises to 51.61%. The ranking at the defaults is a property of the defaults, not of cloud storage.

How the math works

Monthly cost is storage volume multiplied by the storage rate, plus egress volume multiplied by the egress rate. Annual cost is that figure multiplied by twelve. Egress as a percentage of the bill is the egress term divided by the total.

The model is linear, with no tier breaks, no free allowance and no minimum storage duration. It also leaves out operations and request charges, the per-request fees on reads, writes and lists, which are small against storage and transfer for most workloads and stop being small for anything doing many operations on small objects.

The exclusions do not all point the same way, so the figure is neither a floor nor a ceiling. Operations charges, retrieval fees, minimum storage durations and replication options push a real bill above this estimate; free allowances, tier breaks and volume discounts pull it below. What survives both is the comparison between two sets of inputs.

Why run the calculation

Two workloads holding identical volumes can bill very differently, because the second term depends on how often the data is read. An archive that is written once and almost never read bills close to its storage line alone, while a library serving downloads all month can spend more on egress than on storage.

That makes the egress share the useful output. A bill that rose because the data grew and a bill that rose because access patterns changed look the same on the total and quite different once the two lines are separated, and only one of them is fixed by deleting data.

Worked example

A media team stores 5,000 GB of footage and project files at 0.015 per GB a month, and sends 800 GB of finished cuts to clients each month at 0.10 per GB.

• Storage: 5,000 × 0.015 = 75 a month
• Egress: 800 × 0.10 = 80 a month
• Monthly total: 155, of which egress is 51.61%
• Annual total: 1,860

Delivering lower-resolution review copies instead of full-resolution masters cuts monthly egress to 200 GB. The egress line falls to 20, the monthly total to 95 and the annual total to 1,140, with egress down to 21.05% of the bill. Storage did not change at all: the same 5,000 GB at the same rate still costs 75 a month. That cut the annual bill by 38.7%, entirely from the read side.

When this metric matters

The calculation earns its place in a few recurring situations:

• Comparing quoted rates between providers before moving data
• Forecasting annual spend before a new workload is onboarded
• Seeing why a bill rises in a month with heavier retrieval
• Separating a volume increase from an access-pattern change when a bill moves

For educational illustration only

This calculation is an illustration built from the rates and volumes entered rather than a quotation. Real invoices carry line items this model leaves out, in both directions, and published rates move, so the figures above are only as current as the numbers typed into them. The comparison between two scenarios holds better than either scenario's absolute total.