Storage classes
Where each Azure Blob tier stops saving money
An East US LRS comparison of Hot, Cool, Cold, and Archive with byte-level break-even arithmetic, request-price consequences, rehydration time, and a named wrong-choice pattern for every tier.
Put your own numbers through the calculator to see what this meter does to a normal month and to the day you restore.
The access breakpoint compares each lower tier with Hot LRS
Let f be the fraction of stored GB read in an average month. For East US LRS, lower-tier monthly byte cost is its storage rate + f x its retrieval rate. Hot monthly byte cost is $0.0208 per GB because retrieval is not charged. Solving the equality exposes the access frequency where the lower storage rate stops winning. [1]
The formula assumes the object survives its minimum duration and excludes requests, rehydrated-copy storage, and egress. Delete, overwrite, move, or tier change before the minimum can add the prorated remainder. Preserving the Archive source during restoration does not create that early-deletion line. [2] [3]
| Input | East US treatment | Decision rule |
|---|---|---|
| Hot baseline | $0.0208/GB-month and retrieval not charged [1] | Keep Region, redundancy, destination, and unit constant |
| Cool, Cold, or Archive retrieval | f x stored GB x published retrieval rate [1] | A 50% value for f means half the stored bytes are read during the month |
| Minimum duration | Cool 30 days, Cold 90 days, Archive 180 days [2] | The breakpoint is usable only when retention clears the tier minimum |
| Requests | Test separately because read operations rise from $0.0004 to as much as $0.50 per 1,000 [1] | Many small reads move the real crossover toward Hot |
| Internet egress | Excluded only from the relative tier crossover [4] | Add the destination-aware transfer line to the final restore receipt |
Cool and Cold cross over near half a full read per month
The break-even result is a fraction of all stored bytes, so partial reads count. Archive has two results because Standard and High Priority rehydration use different per-GB and per-request prices. [1]
The captured provider record does not publish a minimum billable object size for any Azure tier. That state is not published, not zero and not proof that small objects have no overhead. [2]
| Tier | Storage and retrieval meters | Minimum duration | Break-even versus Hot LRS | Wrong access pattern | Source ref |
|---|---|---|---|---|---|
| Hot LRS | $0.0208/GB-month; retrieval not charged | does not apply | does not apply; this is the online baseline | Long-lived data read below 56% per month when Cool's higher request price and 30-day minimum do not erase the saving | [1] [2] |
| Cool LRS | $0.0152/GB-month + $0.01/GB retrieved | 30 days | ($0.0208 - $0.0152) / $0.01 = 0.56, so 56% per month; 0.56 full reads during the 30-day minimum | More than 56% of stored bytes read per month, delete or overwrite before day 30, or a high count of small reads | [1] [2] |
| Cold LRS | $0.0036/GB-month + $0.03/GB retrieved | 90 days | ($0.0208 - $0.0036) / $0.03 = 0.5733, so 57.33% per month; 1.72 full reads during the 90-day minimum | More than 57.33% read per month, delete or overwrite before day 90, or request-heavy access where $0.01 per 1,000 reads matters | [1] [2] |
| Archive LRS | $0.00099/GB-month; Standard rehydration $0.02/GB, High Priority $0.10/GB | 180 days | Standard: ($0.0208 - $0.00099) / $0.02 = 99.05%. High Priority: $0.01981 / $0.10 = 19.81% | Unplanned reads that cannot wait up to 15 hours, repeated High Priority reads above 19.81% per month, delete or tier change before day 180, or many-small-object restores | [1] [2] [3] |
One million small reads turn a storage comparison into a request comparison
The byte breakpoint treats one 1 GB read and one thousand 1 MB reads as the same retrieved volume. Azure does not bill their operation count the same way. East US read-operation rates rise by 2.5 times in Cool, 25 times in Cold, and 1,250 times in Archive relative to Hot. [1]
Archive also publishes separate Standard and High Priority rehydration request prices. Keep the request definition visible rather than silently adding two fields that may describe the same operation in a particular workflow. [1]
| Tier or rehydration mode | Published request meter | One-million-request arithmetic | Source ref |
|---|---|---|---|
| Hot LRS reads | $0.0004 per 1,000 | 1,000,000 / 1,000 x $0.0004 = $0.40 | [1] |
| Cool LRS reads | $0.001 per 1,000 | 1,000,000 / 1,000 x $0.001 = $1.00 | [1] |
| Cold LRS reads | $0.01 per 1,000 | 1,000,000 / 1,000 x $0.01 = $10.00 | [1] |
| Archive LRS Class B operations | $0.50 per 1,000 | 1,000,000 / 1,000 x $0.50 = $500.00 | [1] |
| Archive Standard rehydration requests | $0.50 per 1,000 | 1,000,000 / 1,000 x $0.50 = $500.00 | [1] |
| Archive High Priority rehydration requests | $5.00 per 1,000 | 1,000,000 / 1,000 x $5.00 = $5,000.00 | [1] |
Copy rehydration keeps the Archive source read-only
Azure can rehydrate an Archive blob by copying it to a new online blob. That path preserves the Archive source, so the restore event itself does not delete, overwrite, move, or change the source tier. Early deletion does not apply for the read-only source. [3]
The receipt can still include the rehydration request, data retrieval, storage for the new Hot or Cool copy, later read operations, and egress to the restore destination. In-place tier changes are a different, mutating workflow and can interact with the 180-day minimum. [2] [3] [4]
| Receipt line | Read-only copy rehydration treatment | Meter state or rate source |
|---|---|---|
| Archive retrieval | Standard or High Priority per-GB rate | $0.02 or $0.10 per GB [1] |
| Rehydration request | Standard or High Priority request rate | $0.50 or $5.00 per 1,000 [1] |
| Temporary or destination copy storage | New online blob is billed in its destination tier for the time retained | conditional [3] |
| Internet egress | Destination and allowance determine the transfer line | conditional [4] |
| Early deletion on the Archive source | No source deletion, overwrite, move, or tier change | does not apply [3] |
| Archive latency | Standard may take up to 15 hours for objects under 10 GB; High Priority may finish in less than 1 hour for objects under 10 GB | conditional [3] |
Sources
Every figure above comes from one of these pages, on the date shown. Each numbered reference in the text links to its entry here. Vendors change prices; if a date looks old, check the source. Three vendors publish a machine-readable feed and the rest are re-checked by hand, which is why the dates are not uniform.
The source ledger4 sources
- 1Azure Retail Prices API: Retail pricesprices.azure.com · checked 2026-07-25 15:34:44+00:00
- 2Microsoft Learn: Access tiers overviewlearn.microsoft.com · checked 2026-07-25 15:34:44+00:00
- 3Microsoft Learn: Archive rehydrate overviewlearn.microsoft.com · checked 2026-07-25 15:34:44+00:00
- 4Microsoft Azure: Bandwidthazure.microsoft.com · checked 2026-07-25 15:34:44+00:00