Amazon S3 vs Backblaze B2 at 100 TB/mo: the real monthly cost
TL;DR — Move it. At 100 TB/mo, Amazon S3 runs about $10,237/month; Backblaze B2 comes to about $995/month — and that includes the time to manage it. That's a 90% lower 5-year total cost and break-even in 0 months, so the numbers clearly favour switching at this scale.
The monthly bill, side by side
| Line | Amazon S3 (AWS) | Backblaze B2 |
|---|---|---|
| Storage (100 TB) | $2,250 | $695 |
| Egress (100 TB/mo) | $7,987 | $0 |
| Ops / management | included | $300 |
| Monthly total | $10,237 | $995 |
$0 egress, kept $0: B2 egress is free up to 3× your stored data — and unlimited free when served through a partner CDN (Cloudflare, bunny.net, Fastly). Front B2 with Cloudflare’s free tier and egress stays $0 at any volume, even past the 3× cap — so the bytes leaving AWS at $0.09/GB leave B2 at $0.
Ops isn't zero, but it's light. Backblaze B2 is still a managed service — the $300/month above is config and monitoring time, not running a cluster. The saving here comes almost entirely from egress that Backblaze B2 doesn't meter the way AWS does.
Break-even & 5-year total cost
Moving costs a one-time $2,000 (data transfer + cutover). At $9,242/month saved, that pays back in 0 months.
| 5-year total cost (incl. ops + migration) | Amazon S3 | Backblaze B2 |
|---|---|---|
| Over 60 months | $614,232 | $61,700 |
| Difference | $552,532 lower (90%) on Backblaze B2 | |
The assumptions (so the numbers are honest)
- 100 TB stored and 100 TB/mo served — a content/media-library profile. Lighter storage shifts the storage line but not the egress story.
- AWS egress is the tiered rate from the egress breakdown ($7,987 at this size); storage at S3 Standard ~$0.023/GB-mo.
- Backblaze B2 is priced from its public rate card; ops labor is priced in, never assumed free.
- Vendor list prices (storage, egress) are confirmed against current rate cards as of 2026-06-26; ops labor & migration are modelled. Your mix of request rates, regions and redundancy will move them — that's what an Assessment nails down.
When to keep Amazon S3 instead
- Low egress — if you serve a few hundred GB a month, the bill is small and a migration won't pay for itself.
- Deep in-region integration — data consumed by other AWS services in-region isn't paying internet egress; fix it with a free VPC endpoint, not a move.
- Spiky, unpredictable traffic that genuinely benefits from scale-to-zero and global presence.
Related
- What 100 TB/mo of Amazon S3 egress costs — the egress line on its own.
- Amazon S3 egress, every scale — the full by-size breakdown.
- Same size, other targets: vs Cloudflare R2 · vs SeaweedFS.
Sources
- Amazon S3 Standard storage pricing — ~$0.023/GB-month — aws.amazon.com/s3/pricing/
- AWS EC2/S3 data-transfer-out pricing — the $0.09/GB first tier and 100 GB free allowance — aws.amazon.com/ec2/pricing/on-demand/
- Backblaze B2 pricing — $6.95/TB-month ($0.00695/GB), free egress up to 3× stored data (and via Cloudflare/bunny.net partners) — www.backblaze.com/cloud-storage/pricing