Storage, requests and egress cost for cloud object storage.
The classic cloud-bill shock is egress, not storage. If you serve lots of downloads, put a CDN in front or pick a provider with free/low egress. For API-side costs see the cloud & dev APIs.
The Object Storage (S3) Cost Calculator estimates your monthly bill for S3-style object storage by combining the three charges that make up nearly every provider's pricing. You enter how much data you keep (storage in GB) at your rate per GB per month, how much data leaves the service (egress in GB) at your per GB egress rate, and your API activity (requests in thousands) at a price per 1,000 requests. The tool multiplies each input by its rate and adds them together, so you can see the total and which of the three drivers — stored capacity, outbound transfer, or request volume — dominates your cost.
The key trade-off to watch is that storage is usually the cheapest line, while egress is often the most expensive and the easiest to underestimate. A bucket that costs little to hold can become surprisingly pricey once users, CDNs, or other regions pull data out of it repeatedly. Request charges matter most for workloads with many small objects or high-frequency reads and writes. Before committing to a provider or architecture, plug in realistic egress and request figures rather than storage alone — modeling those two drivers is what separates an accurate estimate from a bill that surprises you at month's end.
Three parts: storage per GB-month, request fees, and egress (data transfer out) per GB. Storage is cheap; egress is usually the biggest and most surprising line.
Cloud providers price storage low to attract data, then charge heavily to move it out. High-traffic downloads or video can make egress dwarf storage cost — a CDN or an egress-friendly provider mitigates it.
📚 New here? Learn how API pricing works →