Backblaze B2 pricing looks like a one-line calculation until a restore, download spike, or media launch pushes traffic beyond the free egress allowance. For an infrastructure team, the useful question is not just “What does B2 storage cost?” It is “What will this bucket cost after the bytes leave it?”
As of August 2026, Backblaze B2 pay-as-you-go storage starts at $6.95 per TB per 30 days, with the first 10GB free. Standard API calls are free, uploads are free, and downloads are free up to three times average monthly storage; direct egress beyond that allowance costs $0.01/GB.
That is the short answer. The rest of this guide turns it into a bill you can model.
Backblaze B2 pricing at a glance
The current Backblaze B2 pricing page separates the service into pay-as-you-go B2, contracted B2 Reserve capacity, and B2 Overdrive for high-throughput, multi-petabyte workloads. Most teams evaluating B2 storage mean the standard pay-as-you-go product.
| Cost line | Current pay-as-you-go treatment | What to model |
|---|---|---|
| Storage | $6.95/TB per 30 days | Average stored bytes, measured by byte-hour |
| Free storage | First 10GB | Small tests and light personal workloads |
| Uploads | Free | Your source-side network or migration tool may still charge |
| Downloads | Free up to 3× average monthly storage | Total bytes downloaded during the billing cycle |
| Egress over allowance | $0.01/GB | Only bytes above the 3× allowance |
| Class A, B, and C API calls | Free | Request volume still affects performance and design |
| Class D transactions | First 2,500 per day free, then $0.004 per 10,000 | Event Notifications activity |
| Minimum file size or retention | None | No early-deletion term to add |
This is the post-May 1, 2026 price card. Backblaze’s March 2026 product update raised storage from $6/TB to $6.95/TB and removed fees for standard API calls. Existing committed contracts keep their contracted rate until renewal, so an invoice may differ from the public pay-as-you-go price.
How Backblaze B2 pricing works
Use this simplified monthly formula:
B2 cost = billable average storage + excess direct egress + Class D transactions + optional support or contract charges
The formula is short, but three inputs need care.
Storage is an average, not a month-end snapshot
Backblaze bills storage monthly from byte-hours. The provider describes the published rate as $6.95/TB per 30-day period, but the charge follows how much data was present over time. Uploading 20TB on the final day does not create the same storage charge as holding 20TB for the full cycle.
Use average stored bytes from telemetry rather than the largest or final bucket size. Include old object versions, incomplete cleanup, retained backups, and every copy your workflow deliberately keeps.
The 3× egress allowance follows average storage
The official egress explanation says the free allowance is three times average monthly storage, with that average also based on byte-hours. If a bucket averages 10TB, up to 30TB of download in the cycle is free. If it averages 2TB, the allowance is 6TB—not three times the 10TB briefly present before a cleanup.
For direct internet downloads, calculate:
excess egress GB = max(0, downloaded GB - 3 × average stored GB)
Then multiply excess egress by $0.01/GB. Downloads to or through approved CDN and compute partners can receive unlimited free egress instead; confirm the current partner and routing requirements on Backblaze’s integration directory before treating that path as free.
API calls are mostly free, not literally all free
The 2026 update removed charges for standard calls. Backblaze’s live pricing table identifies Class A, B, and C calls as free for pay-as-you-go accounts, while Class D Event Notifications transactions retain a price after a daily allowance.
Do not let “free API calls” end capacity planning. Listings, range reads, retries, multipart uploads, lifecycle jobs, and cache revalidation can still affect latency, application behavior, and downstream traffic even when their request line is $0.
Backblaze B2 pricing examples
The examples below use the displayed decimal units—1TB equals 1,000GB—and round away the first 10GB free tier so the workload comparison stays readable. They exclude taxes, paid support, negotiated terms, and Class D transactions.
| Average storage | Monthly direct downloads | Free egress allowance | Egress overage | Approximate monthly cost |
|---|---|---|---|---|
| 1TB | 1TB | 3TB | $0 | $6.95 |
| 10TB | 20TB | 30TB | $0 | $69.50 |
| 10TB | 50TB | 30TB | $200.00 | $269.50 |
| 100TB | 400TB | 300TB | $1,000.00 | $1,695.00 |
The third row shows the threshold clearly. Ten terabytes stored costs about $69.50, but serving five times that footprint directly adds $200. The storage rate did not change; the traffic-to-storage ratio did.
The fourth row shows why “egress is free” is an unsafe shorthand. B2’s allowance is generous for backups, restores, and moderate delivery, but a high-turnover download workload can still make outbound traffic the largest line.
A bursty bucket needs byte-hour math
Suppose a media team uploads 10TB halfway through a 30-day cycle and holds it through month end. Its simplified average storage is about 5TB, so its approximate free egress allowance is 15TB—not 30TB. If viewers download 25TB that month, roughly 10TB is over the allowance and adds about $100.
Actual billing follows precise byte-hours rather than this half-month shortcut. Export usage data and calculate against the account’s real cycle before approving a forecast.
What the headline Backblaze B2 cost misses
S3 compatibility is not workload identity
Backblaze exposes both a Native API and an S3-Compatible API. Its API overview says both cover authentication, bucket management, uploads, downloads, and listings, while differing in areas such as key management, SDKs, presigned URLs, and file uploads.
“S3-compatible” can reduce migration work, but it does not prove that every SDK feature, IAM assumption, endpoint behavior, lifecycle rule, or observability integration will behave exactly as it did on AWS. Run compatibility tests with your actual client, multipart settings, presigned URL flow, and error handling.
Free egress does not price viewer delivery
Free transfer from B2 to an approved CDN partner removes one boundary. It does not make the CDN’s requests to viewers, cache misses, purge behavior, regional rates, or optional services free. Model origin egress and viewer delivery as separate rows.
For public media, downloads, and game assets, include cache-hit ratio, range requests, traffic geography, invalidation frequency, and traffic spikes. The cache invalidation guide explains why aggressive purges can turn cacheable traffic back into origin traffic.
Operational controls still matter
Backblaze lets customers set caps for storage and Class A, B, and C activity, and alerts at 75% and 100% of a cap. Its data caps documentation warns that without caps, usage and charges can continue without a ceiling. Class D caps are not available, so Event Notifications need separate monitoring.
Cost predictability also depends on object lifecycle, replication outside B2, source-side transfer, support, recovery tests, and the labor required to operate the path. None changes the $6.95 headline, but all belong in a production decision.
Model Backblaze B2 pricing for your workload
Build three scenarios: an ordinary month, a growth month, and a failure or viral-spike month. Give each scenario these inputs:
- Average stored GB derived from byte-hours.
- New uploads and deleted bytes during the cycle.
- Direct downloads and partner-routed downloads as separate totals.
- Cache-hit ratio and expected origin fills if a CDN sits in front.
- Class D Event Notifications calls by day.
- Replicas, backups, versions, and temporary objects outside the main bucket.
- Support, taxes, contractual discounts, and migration costs.
Then compare architectures, not isolated storage cells. Backblaze B2 is compelling when low always-hot storage cost and a 3× egress allowance fit the workload. A combined storage-and-delivery platform is easier to forecast when the same content is served repeatedly around the world.
For that second case, ZeroBuffer pricing pairs S3-compatible storage at $0.01/GB per month per replica with global CDN delivery from a flat $0.0049/GB across regions. That storage rate is higher than B2’s headline, so compare the complete path: stored capacity, origin transfer, CDN delivery, encoding where relevant, and operational fit.
When Backblaze B2 is the right choice
B2’s pricing shape fits especially well when stored data is large relative to monthly downloads:
- Backup repositories with controlled restores.
- Active archives without minimum retention penalties.
- Application storage whose traffic stays below three times average capacity.
- Workloads routed through an approved free-egress partner.
- Teams that value a simple always-hot tier and free standard transactions.
Look harder at the complete architecture when downloads repeatedly exceed the allowance, the bucket is an origin for global media, or a short-lived upload creates a low byte-hour average before a large distribution event. In those cases, the decisive number is cost per delivered GB, not cost per stored TB.
B2 Reserve may suit a stable, committed capacity baseline, while B2 Overdrive starts at $15/TB/month for high-throughput multi-petabyte requirements and includes unlimited egress. Both change the commercial model, so request a quote using the same traffic assumptions as the pay-as-you-go comparison.
Frequently asked questions
How much does Backblaze B2 cost per month?
Pay-as-you-go B2 storage starts at $6.95 per TB per 30 days, calculated from byte-hours, with the first 10GB free. Add $0.01/GB for direct egress above three times average monthly storage, Class D Event Notifications charges above the daily allowance, and any optional support or contract costs.
Is Backblaze B2 egress free?
It is free up to three times average monthly storage. Egress above that allowance costs $0.01/GB for direct downloads, while transfer to or through approved CDN and compute partners can be unlimited and free under the partner program.
Does Backblaze B2 charge for API requests?
Class A, B, and C API calls are free for pay-as-you-go customers as of May 1, 2026. Class D transactions associated with Event Notifications cost $0.004 per 10,000 calls after the first 2,500 calls each day.
Is Backblaze B2 free for the first 10GB?
Yes. The first 10GB of B2 storage is free. Downloads, API behavior, and any other applicable services still follow their own allowances and terms.
Is Backblaze B2 cheaper than S3-compatible alternatives?
It depends on the workload. B2 has a low storage rate, no minimum storage duration, free standard API calls, and a large egress allowance; an alternative can still cost less when its delivery rate, retention rules, regional pricing, or integrated CDN better matches your traffic pattern.
Calculate the path, then choose the bucket
Backblaze B2 pricing is straightforward only after average storage and outbound traffic are measured together. At or below three times average storage, the $6.95/TB rate can stay close to the total. Above that line, direct egress becomes a separate cost center; with a partner CDN, viewer delivery replaces it as the line to model.
Take one month of real byte-hours, downloads, and cache data and price all three scenarios before migrating. If delivery dominates, test the full storage-to-viewer path—not another storage cell—and run a proof of concept against the traffic spike your production system actually has to survive.
ZeroBuffer exists to be that whole path in one place: S3-compatible storage at $0.01/GB-month per replica, flat CDN delivery from $0.0049/GB with no egress allowance ratio to police, origin shielding and instant purge across 100+ edge locations, and free multi-rendition encoding. Because there are no contracts and no minimums, the proof of concept costs a test workload rather than a commitment. Compare it against your B2 numbers.