How to Estimate Cloud Storage Cost: Amazon S3 vs Azure Blob

The price per GB is the number everyone compares, and it is rarely the number that decides your bill. Here is what actually adds up on Amazon S3 and Azure Blob Storage, and a simple way to estimate it before you commit.

Open the Cloud Storage Cost Calculator

A cloud storage bill has five parts: storage (per GB per month), requests (every read and write), retrieval (a per-GB fee to read data from cooler classes), data transfer out (egress, the fee to move data out to the internet) and early deletion (a charge if you delete data before the class's minimum storage time). A class with a very low price per GB usually charges more for the other four.

That is why storage classes exist. Amazon S3 offers Standard, Intelligent-Tiering, Standard-IA, One Zone-IA, Glacier Instant Retrieval, Glacier Flexible Retrieval and Glacier Deep Archive. Azure Blob Storage offers Hot, Cool, Cold and Archive. Hot classes cost more to store and little to read. Cool and cold classes cost less to store but add retrieval fees. Archive classes are the cheapest to store, but data must be restored first, which takes hours.

Minimum storage time is the part people miss. Standard-IA and Azure Cool bill at least 30 days, Glacier Instant Retrieval and Azure Cold at least 90 days, and Deep Archive and Azure Archive at least 180 days. If you delete or replace data sooner, you still pay for the full period. Data that changes every week should not live in an archive class.

Small files can cost extra too. S3 Standard-IA, One Zone-IA and Glacier Instant Retrieval bill each object as if it were at least 128 KB, so millions of tiny files in a cool class can cost more than keeping them in Standard.

To estimate your own cost, write down six numbers: how much data you store today, how fast it grows, how often you read it, how much you read each month, how much leaves the cloud (egress), and how long you keep it. With those, you can add up each class and compare the total, not the price per GB. The cheapest class is the one with the lowest total for your pattern.

The Cloud Storage Cost Calculator does this sum for you. Enter your data size, growth, reads and writes, retrieval, egress, retention and how often the data is accessed. It adds up storage, requests, retrieval, egress and early-deletion charges for every S3 and Azure Blob class, recommends the cheapest class that fits (and tells you when it needs a restore wait), shows what happens when your data grows 2x, 5x or 10x, and exports a PDF, Excel or CSV report.

Prices come from the official AWS Price List and the Azure Retail Prices API, with the download date shown on the page, and a price that cannot be matched is never guessed. Google Cloud Storage classes are listed, but Google prices are not loaded yet, so they show as pending and are not part of the comparison.

Treat the result as an estimate, not a quote. It uses public pay-as-you-go list prices, so discounts, taxes, committed-use deals and free tiers are not included. Nothing you type is uploaded, and if you measure a sample file to see how well your data compresses, that file stays in your browser.

Three habits lower most storage bills: keep data that is read often in a hot class, move data you rarely read to a cool or cold class only if you will keep it past the minimum time, and compress or convert big CSV and JSON files to Parquet before you store them, because fewer bytes cost less to store and to move.

Open the Cloud Storage Cost Calculator

Related tool pages

  • AWS S3 Cost Calculator: Estimate your Amazon S3 bill by class: Standard, Intelligent-Tiering, Standard-IA, One Zone-IA and Glacier, with requests, retrieval and egress. Free.
  • Azure Blob Storage Cost Calculator: Estimate Azure Blob Storage costs for Hot, Cool, Cold and Archive (LRS): storage, operations, retrieval and bandwidth, from official Azure prices. Free.
  • Amazon S3 vs Azure Blob Storage Cost: Compare Amazon S3 and Azure Blob Storage for your data size, growth, access and egress, class by class, with the cheapest option highlighted. Free.
  • S3 Glacier Cost Calculator: The real cost of S3 Glacier Instant, Flexible Retrieval and Deep Archive: storage, retrieval, requests and minimum days, compared with Azure Archive.

How to use the Cloud Storage Cost Calculator: step by step

  1. Open the Cloud Storage Cost Calculator.
  2. Choose providers and a region.
  3. Describe your data: size, growth, reads, retrieval, egress and retention.
  4. Review the cheapest class that fits and download the report.

When to use the Cloud Storage Cost Calculator

  • Compare Amazon S3 and Azure Blob before you migrate data
  • Check whether Glacier or Azure Archive really saves money for your access pattern
  • Plan a budget when data will grow 2x, 5x or 10x
  • Export a PDF cost report for a manager or a client

Example

Input: 10 TB, 500 GB growth a month, occasional access, 200 GB retrieval

Output: Best fit, cost per month and per year, 2x / 5x / 10x growth

Frequently asked questions

Which cloud is cheapest for storage?

It depends on how you use the data. The lowest price per GB is often not the cheapest once requests, retrieval, egress and minimum-duration charges are added, so this tool compares your whole workload, class by class.

Which storage classes are compared?

Amazon S3 Standard, Intelligent-Tiering, Standard-IA, One Zone-IA, Glacier Instant Retrieval, Glacier Flexible Retrieval and Glacier Deep Archive, and Azure Blob Storage Hot, Cool, Cold and Archive (LRS). Google Cloud Storage classes are listed, and their prices show as unavailable until Google prices are loaded.

How accurate is it?

It uses the providers' official pay-as-you-go list prices for the region you choose, with tiered pricing, minimum storage durations, early-deletion fees and minimum billable object sizes. It is an estimate, not a quote: discounts, taxes, reserved capacity and free tiers are not included.

Do I need a cloud account or to upload data?

No. You describe your data size and access pattern. An optional sample file is measured in your browser (compression and duplicate rows) and never uploaded.

Tip: Look at the total, not the price per GB. Retrieval, requests and egress often cost more than the storage itself.