Twenty years ago I was a systems engineer designing new financial systems. The task I enjoyed least was working out the Microsoft licensing: per seat or per user, with or without Software Assurance. Cloud computing promised simpler pricing: pay for what you use. When I looked at cloud storage costs recently, the answers turned out to be far from simple, so I built the calculator below to compare the providers.

Each of the six major cloud object storage providers sells functionally the same thing: durable file storage over HTTP. Yet costs vary considerably. Storing a terabyte and downloading it once a month costs anywhere from $7 to over $130 depending on the provider.

Amazon created the category in 2006, launching S3 at $0.15 per gigabyte-month. Microsoft and Google soon followed, and a group of challengers (Backblaze B2, Wasabi, Cloudflare R2) now competes on simpler pricing: free egress, free API calls, flat rates. The cheapest providers now charge a twentieth of that, and S3 itself about a sixth; the pricing models have only grown more intricate.

Which charge matters most depends on the workload: serving video is egress-heavy, backups are storage-heavy, log pipelines mean millions of small objects, archives are storage-only. There is no cheapest provider, only a cheapest provider for a specific workload.

Storage calculator

Describe your workload and see what each provider would charge, cheapest first. The calculator checks every storage class each provider offers and shows each at its cheapest for your inputs. Drag the downloads slider and the ranking reshuffles.

Billing components

Storage. Billed per GB-month. Backblaze charges under a cent; Amazon in London charges three and a half times that. Archive tiers go as low as about $1 per TB-month in US regions, with the trade-offs below.

Egress. Ingress is free on every provider. Amazon and Microsoft charge around $90 per TB for internet egress, and Google $120; the challengers include it, which is how the same workload costs $7 on Backblaze and over $100 on AWS. Wasabi’s free egress is capped by a fair-use policy: monthly egress must not exceed the volume stored.

API requests. Uploads, downloads and listings are billed per operation. The cost is negligible for most workloads, but with millions of small objects it can exceed the storage charge. Backblaze and Wasabi do not charge for requests.

Retrieval fees. Archive tiers charge per GB retrieved. S3 Glacier Flexible Retrieval, Glacier Deep Archive and Azure Archive are not online tiers: objects must be restored first, which takes hours.

Minimum term. Archive tiers bill a minimum storage duration of 30 days to a year, regardless of when objects are deleted. Wasabi applies 90 days to all objects; Backblaze has no minimum.

Redundancy. List prices assume different levels of redundancy. S3 Standard spans at least three availability zones and Google regional storage spans multiple zones. Azure’s headline price is for LRS, a single datacentre; ZRS costs 10–30% more. Compare like for like before concluding that Azure is cheaper.

Region. Amazon’s Ireland and Google’s Belgium regions are priced the same as the US; Azure’s West Europe prices differ by tier. London carries a premium of up to double on archive tiers. The flat-rate providers price every region the same, though only Wasabi has UK datacentres.

Caveats

Small objects. Infrequent-access tiers have a minimum billable object size: 128 KB on S3, including Glacier Instant Retrieval. A million small objects can cost several times their raw size; aggregate them, or keep them on the standard tier.

Volume pricing. Tiered discounts apply above roughly 50 TB. The calculator does not model them, so it slightly overstates large bills.

Stale data. Backblaze and Wasabi both raised prices in 2026, and many published comparisons still show the old rates. Every figure here was checked against official pricing pages and APIs on the date below.

Assumptions. Pay-as-you-go list prices in US dollars, single region, excluding VAT, discounts and free-tier allowances.

Disclaimer

All figures, including the calculator’s output, are estimates from public list prices, not quotes. Validate them against the providers’ own pricing calculators before committing spend. I have no affiliation with any provider. Errors are mine, and corrections are welcome.

Prices verified against official sources: 10 October 2026. List prices change; check current rates if this date is several months old.

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