Cloud Storage Cost Calculator

Understanding the cloud storage cost calculator — concept and principle

Cloud object storage is usually billed on two main meters: how much data you keep each month (GB-months) and how much data leaves the provider's network (egress). This calculator estimates the first month's bill and the total over a period when your stored data grows by a steady percentage each month. Use it for budgeting, comparing providers or tiers, and seeing how growth and egress drive cost.

Storage grows 3% a month while egress stays at 90; the year adds up to about 4,344.17.

How it is calculated

Monthly cost = stored TB × 1000 × price per GB-month + egress TB × 1000 × egress price per GB.
Growth: after each month the stored amount is multiplied by (1 + growth ÷ 100); egress stays constant.
Total = the sum of the monthly costs over the chosen number of months.

1 TB is treated as 1000 GB. The currency is whatever your prices are in.

The principle

Storage charges accumulate like a running meter: every gigabyte you keep for a month costs the per-GB-month price. With compound growth g, the storage part of the total is a geometric series, first-month storage cost × ((1 + g)ᵐ − 1) ÷ g. Egress is billed per gigabyte transferred out, so a fixed monthly egress adds the same amount every month. For many workloads egress is a surprisingly large share, because its per-GB price is several times the storage price.

Worked example

Inputs: 10 TB at 0.023 per GB-month, 1 TB egress at 0.09 per GB, 3% monthly growth, 12 months.
First month: storage 10,000 × 0.023 = 230; egress 1000 × 0.09 = 90; total 320.
Storage reaches 10 × 1.03¹¹ ≈ 13.84 TB in month 12, costing about 318.37 plus 90 egress.
Storage over 12 months: 230 × (1.03¹² − 1) ÷ 0.03 ≈ 3,264.17.
Egress over 12 months: 90 × 12 = 1,080.
Total: 3,264.17 + 1,080 ≈ 4,344.17.

Each point is the calculator re-run with only “Data stored (TB)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Data stored (TB)	First month cost
2.5	147.5
5	205
7.5	262.5
10	320
12.5	377.5
15	435
20	550

How to read the result

Compare the storage and egress shares. If storage dominates, consider lifecycle rules that move old data to cheaper infrequent-access or archive tiers, and delete what you no longer need. If egress dominates, a CDN, caching or keeping compute in the same region can cut it.

Common mistakes

Using example prices instead of your provider's current list price for your region and tier.
Forgetting request charges (per PUT/GET), retrieval fees and minimum storage durations on cold tiers.
Ignoring tiered pricing, where the per-GB price falls after certain volumes.

Keep in mind: This is a simplified estimate, not a quote and not financial advice. Real bills include request, retrieval, replication and tax charges and can use discounts or free allowances.

Frequently asked questions

Is egress charged for uploads?

Data transfer into most public clouds is typically free; charges usually apply to data going out to the internet or across regions.

Why does growth matter so much?

It compounds: 3% per month is about 42.6% more data after a year.

Are cold or archive tiers always cheaper?

Storage is cheaper, but retrieval fees, slower access and minimum storage periods can make them more expensive for data you read often.

Sources: Amazon S3 pricing, aws.amazon.com/s3/pricing · Google Cloud Storage pricing, cloud.google.com/storage/pricing

Checked 8 Nov 2026. Standard formulas and RFC/IEEE definitions, computed locally in your browser — nothing you type is sent anywhere.

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