Azure SQL Hyperscale storage cost for 100 TB kept for 7 days vs 30 days

Question

Azure SQL Hyperscale storage cost for 100 TB kept for 7 days vs 30 days

Anonymous

Hello Microsoft team, We want to validate how Hyperscale storage billing works for short durations.

Scenario

Service tier: Azure SQL Database Hyperscale

Region: <enter region>

Currency: <enter currency>

Storage price shown on the pricing page: <enter GB-per-month rate for the region, for example 0.25 USD per GB-month>

Allocation size: 100 TB (we understand Hyperscale allocates in 10 GB steps and charges for actual allocated size)

No change in size within each scenario

Questions in simple terms

If we keep 100 TB allocated for 7 days only, and then drop it, how much will we pay for storage?

If we keep the same 100 TB allocated for 30 days, how much will we pay?

The pricing page says storage is billed in GB per month and prorated hourly. Can you please confirm that the math is: Cost = Allocated_GB × Price_per_GB-month × (hours_kept ÷ hours_in_month) and, for a simple estimate, Cost ≈ Allocated_GB × Price_per_GB-month × (days_kept ÷ days_in_month).

For the GB conversion, should we use 1 TB = 1024 GB or 1 TB = 1000 GB for this meter?

Do default Hyperscale backups change the answer for these two scenarios, assuming default retention only and no long-term backup configured?

Optional example for you to confirm If the regional rate is 0.25 USD per GB-month and we treat 1 TB as 1024 GB:

100 TB = 102,400 GB

Monthly cost example ≈ 102,400 × 0.25 = 25,600 USD

Seven days in a 30-day month ≈ 25,600 × 7 ÷ 30 = 5,973.33 USD

Thirty days ≈ 25,600 USD Please confirm whether this example and the formula are correct for Hyperscale storage.

Mahesh Kurva 10,520 Reputation points Microsoft External Staff Moderator

2025-09-04T18:20:46.6933333+00:00

Hi @Janice Chi ,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Mahesh Kurva 10,520 Reputation points Microsoft External Staff Moderator

2025-09-05T17:29:39.3966667+00:00

Hi @Janice Chi ,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.

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Mahesh Kurva 10,520 Reputation points Microsoft External Staff Moderator

2025-09-04T18:20:46.6933333+00:00

Hi @Janice Chi ,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Mahesh Kurva 10,520 Reputation points Microsoft External Staff Moderator

2025-09-05T17:29:39.3966667+00:00

Hi @Janice Chi ,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.

Answer 1

Hi @Anonymous ,

Greetings!!

It sounds like you're trying to get a handle on the storage costs for Azure SQL Database Hyperscale in different scenarios. Let’s break down the calculations based on the information you provided.

1.Billing Formula Confirmation

Yes, your understanding is correct. Azure bills Hyperscale storage hourly, based on the allocated size, using the formula:

Hourly prorated cost:

Cost=Allocated GB×Price per GB-month×(Hours keptHours in month)\text{Cost} = \text{Allocated GB} \times \text{Price per GB-month} \times \left( \frac{\text{Hours kept}}{\text{Hours in month}} \right)Cost=Allocated GB×Price per GB-month×(Hours in monthHours kept)

For a simple estimate, this can be approximated as:

Cost≈Allocated GB×Price per GB-month×(Days keptDays in month)\text{Cost} \approx \text{Allocated GB} \times \text{Price per GB-month} \times \left( \frac{\text{Days kept}}{\text{Days in month}} \right)Cost≈Allocated GB×Price per GB-month×(Days in monthDays kept)

2.GB Conversion:

1 TB = 1024 GB

Azure uses binary conversion for storage billing, so:

1TB = 1024 GB

Therefore, 100 TB = 102,400 GB

3.Cost Calculation Examples

Assuming:

Price per GB-month = $0.25

Allocated size = 100 TB = 102,400 GB

For 30 days:

102,400×0.25=$25,600102,400 \times 0.25 = $25,600102,400×0.25=$25,600

For 7 days (in a 30-day month):

25,600×730≈$5,973.3325,600 \times \frac{7}{30} \approx $5,973.3325,600×307≈$5,973.33

These calculations are correct and match how Azure bills Hyperscale storage.

4.Impact of Hyperscale Backups

With default backup retention (typically 7 days) and no long-term backup configured, the storage cost does not change for your scenarios. Hyperscale backups are stored in separate storage and billed separately under Backup Storage, which is free up to the retention period for most configurations.
Only incurs cost if additional backup storage is used (e.g., long-term retention or large DBs with frequent changes).
So for your 7-day and 30-day scenarios with default retention, no additional cost is expected from backups.

For more information, please refer the document:

Azure SQL Database pricing.

Automated backups for Hyperscale databases.

I hope this information helps. Please do let us know if you have any further queries.

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Azure SQL Hyperscale storage cost for 100 TB kept for 7 days vs 30 days

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