Compare monthly storage and egress costs on AWS S3, Cloudflare R2 and Backblaze B2.
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The Cloud Storage Cost Calculator turns average stored data, monthly requests and egress into monthly and yearly cost on AWS S3, Cloudflare R2 and Backblaze B2, sorted for comparison. Formula: storage (tiered rate × GB beyond the free amount) + requests + egress + retrieval. It also offers a growth forecast, an egress break-even and custom plans, with price sources, page dates and the verification date listed below.
It covers AWS S3 (Standard, Standard-IA and Glacier Instant Retrieval, US East region), Cloudflare R2 (Standard and Infrequent Access) and Backblaze B2. Google Cloud Storage's price table could not be read reliably, so it is not in this first version; use the custom plan to enter any provider's quote.
Egress is data sent from the storage service out to the internet. Storing data is cheap, but the transfer fee to send it out can far exceed the storage fee, so read-heavy uses (downloads, media, model weights) are the ones most often hit by egress charges. R2 charges nothing for egress, B2 is free up to 3× the average data stored, and S3 is tiered by volume.
According to the official page, B2 egress is free up to 3× the average monthly data stored, with the excess billed per GB; traffic through Backblaze's CDN and compute partners has separate free terms. The tool applies the first rule and does not model partner traffic.
Infrequent-access classes (such as S3 Standard-IA and R2 Infrequent Access) and Glacier Instant Retrieval have a lower storage rate but charge a per-GB retrieval fee whenever data is read back, and their request prices are higher. If data is read often, the total can end up above Standard. These classes also usually have minimum storage durations and minimum billable object sizes, which this tool does not model.
AWS prices come from the official AWS Price List, Cloudflare and Backblaze prices from their official pricing pages, with sources and verification date shown under the tool. The data is a hand-maintained static file, and a warning appears if it has not been verified for more than 45 days. Prices can change at any time, so treat results as estimates and confirm on the official pages before important decisions.
"Write / list requests" map to S3 PUT, COPY, POST and LIST and to R2 Class A; "read requests" map to S3 GET and other requests and to R2 Class B. Monthly counts can come from your account's usage report or access logs. B2's ordinary transactions are free, so they do not affect its result.
It excludes tax, negotiated or committed-use discounts, cross-region replication and transfer, lifecycle-transition requests, management features (inventory, analytics), the AWS account-level monthly free egress, CDN charges, and the minimum storage duration and minimum billable object size of each class. All of these can affect a real bill.
| Plan | Storage | Requests | Egress | Retrieval | Per month | Per year |
|---|---|---|---|---|---|---|
| Backblaze B2 Cloud StorageLowest | $6.88 | $0.00 | $0.00 | $0.00 | $6.88 | $82.57 |
| Cloudflare R2 Standard | $14.85 | $0.00 | $0.00 | $0.00 | $14.85 | $178.20 |
| Amazon S3 Standard | $23.00 | $9.00 | $45.00 | $0.00 | $77.00 | $924.00 |
Price sources and verification
Data verified on 2026-10-20
This tool is not affiliated with AWS, Cloudflare or Backblaze. Prices are public standard USD list prices, excluding tax, negotiated pricing, committed-use discounts and other charges such as cross-region replication; use them for estimates only.
