Is Lightsail data transfer allowance based on the current number of instances or the monthly peak number of instances for a bundle?

Question

I would like to clarify how Amazon Lightsail calculates the aggregated monthly data transfer allowance for instances with the same `bundleId` in the same AWS Region.

For a given Lightsail bundle, at any point in time during a billing month, is the total available data transfer allowance calculated as:

```text
Current total allowance
= current number of existing instances with that bundleId
  × data transfer allowance per instance
```

Or is it calculated based on the maximum number of instances with that bundleId that existed at any point earlier in the same billing month, such as:

```text
Current total allowance
= maximum number of instances with that bundleId that have existed simultaneously so far this month
  × data transfer allowance per instance
```

For example, assume the `nano_ipv6_3_0` bundle includes **1,024 GB/month** of data transfer allowance per instance.

Scenario 1:

```text
At the beginning of the month:
5 instances of nano_ipv6_3_0 are created.

After one hour:
All 5 instances are deleted.

Later in the same month:
1 new nano_ipv6_3_0 instance is created.
```

At this point, is the aggregated allowance for this bundle in this Region:

```text
1 × 1,024 GB = 1,024 GB
```

because only one instance currently exists,

or:

```text
5 × 1,024 GB = 5,120 GB
```

because five instances existed simultaneously earlier in the same billing month?

Scenario 2:

```text
At the beginning of the month:
5 instances of nano_ipv6_3_0 are created.

After one hour:
All 5 instances are deleted.

Later in the same month:
10 new nano_ipv6_3_0 instances are created.
```

At this point, is the aggregated allowance:

```text
10 × 1,024 GB = 10,240 GB
```

based on the ten instances currently existing,

or is there another calculation method that takes the previously deleted five instances into account?

In short, for the same `bundleId` within the same Region, is Lightsail’s monthly data transfer allowance pool based on the **current instance count**, the **maximum simultaneous instance count so far in the month**, or some other billing calculation?

Florian Turnwald · Answer

Amazon Lightsail’s monthly data transfer allowance is based on **the cumulative, pro-rated hours of all instances (both active and deleted)** of the same bundle type in that Region during the billing month.
It is **not** based on the current instance count, nor is it based on the peak simultaneous count.
### my understanding how it works:
 * **Hourly Pro-ration:** Lightsail pro-rates data transfer hourly. For example, a bundle with a 1,024 GB/month allowance contributes approximately **1.42 GB per hour** (1,024 	ext{ GB} / 720 	ext{ hours}) to your regional pool for every hour it runs.
 * **Deleted Instances:** When you delete an instance, the pro-rated allowance it accumulated while it was active **remains** in your pool for the rest of that billing cycle.

**Summary:** Your total allowance pool is the sum of the hourly data transfer credits earned by every instance that existed during the month, calculated by their total lifespan.

re:Post Agent · Answer

Based on Amazon Lightsail's data transfer allowance model, the aggregated data transfer allowance is calculated based on the **current number of instances** with the same bundleId in a Region, not the monthly peak or maximum number that existed simultaneously.

However, there's an important nuance: **deleting an instance and creating a new instance does not reset the data transfer allowance**. This means that while your allowance is based on currently existing instances, any data transfer that occurred before you deleted instances still counts against your total usage for the month.

For your scenarios:

**Scenario 1:** When you have 1 instance of nano_ipv6_3_0 running later in the month, your current aggregated allowance would be **1 × 1,024 GB = 1,024 GB**. However, any data transfer that occurred during the hour when the 5 instances were running still counts toward your monthly usage. So if those 5 instances transferred significant data during that hour, you could potentially exceed your current 1,024 GB allowance even though you only have 1 instance now.

**Scenario 2:** With 10 instances of nano_ipv6_3_0 currently running, your aggregated allowance would be **10 × 1,024 GB = 10,240 GB**. Again, any data transfer from the previously deleted 5 instances counts toward your total monthly usage, but your allowance is based on the 10 currently existing instances.

The key principle is that data transfer allowance aggregates across instances of the same bundle in a Region based on what's currently running, but usage accumulates throughout the entire month regardless of instance creation and deletion.  
**Sources**  
[Data transfer in Lightsail - Amazon Lightsail](https://docs.aws.amazon.com/lightsail/latest/userguide/amazon-lightsail-faq-data-transfer-allowance.html)  
[Amazon Lightsail Pricing](https://aws.amazon.com/lightsail/pricing/)

Is Lightsail data transfer allowance based on the current number of instances or the monthly peak number of instances for a bundle?

my understanding how it works:

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