# Understanding your reservations
You can use the AWS Cost and Usage Reports (AWS CUR) to track your Reserved Instance (RI) utilization, charges, and allocations. This section is an in-depth description to understand your reservations.
**Topics**
+ [Understanding your reservation line items](regular-reserved-instances.md)
+ [Understanding your amortized reservation data](amortized-reservation.md)
+ [Monitoring your size flexible reservations for Amazon EC2](monitor-flexible-reservation.md)
+ [Monitoring your On-Demand capacity reservations](monitor-ondemand-reservations.md)
# Understanding your reservation line items
RIs provide you a significant discount compared to On-Demand Instance pricing. RIs aren't physical instances. They're a billing discount applied to the use of On-Demand Instances in your account. These On-Demand Instances must match certain attributes to benefit from the billing discount.
**Topics**
+ [Upfront fee](#upfront-fee)
+ [True-up fee](#true-up-fee)
+ [Recurring monthly RI fee](#recurring-monthly)
+ [RI discount benefits](#discount-benefits)
+ [Reserved Instance type](#ri-type)
+ [Reserved Instance benefits applied to instance usage](#ri-instance-usage)
**Note**
In the following tables, the columns and rows from AWS CUR are transposed for clarity. The values in the first column represent the headers of a report. These examples include only a few key AWS CUR columns. To learn more about other AWS CUR columns, see the [Data dictionary](data-dictionary.md).
## Upfront fee
The **Fee** line item is added to your bill when you purchase an `All Upfront` or `Partial Upfront` RI.
The following table shows how this one-time fee appears in some AWS CUR columns.
| | |
| --- |--- |
| lineItem/LineItemType | Fee |
| lineItem/ProductCode | AmazonEC2 |
| lineItem/UsageStartDate | 2016-01-01T00:00:00Z |
| lineItem/LineItemDescription | Sign up charge for subscription: 363836886, planId: 1026576 |
| lineItem/UnblendedCost | 68 |
| Reservation/ReservationARN | arn:aws:ec2:us-east-1:123456789012:reserved-instances/f8c204c1-dd48-43f1-adb8-f88aa61e0dea |
## True-up fee
If you exchange a Convertible Reserved Instance, any cost associated with the exchange of the original Reserved Instance and the new Reserved instance (true-up fee) is also added to your bill as a **Fee** line item. For a true-up fee, the **reservation/ReservationARN** column contains **reserved-instance-exchange/riex**.
The following table shows a true-up fee from exchanging a Convertible Reserved Instance.
| lineItem/LineItemType | lineItem/ProductCode | lineItem/UsageStartDate | lineItem/LineItemDescription | lineItem/UnblendedCost | Reservation/ReservationARN |
| --- | --- | --- | --- | --- | --- |
| Fee | AmazonEC2 | 2016-01-01T00:00:00Z | | | arn:aws:ec2:eu-west-1:012345678901:reserved-instance-exchange/riex-examplef-5d71-4215-886f-17a3f64ea972 |
## Recurring monthly RI fee
The **RI Fee** line item describes the recurring monthly charges that are associated RIs applied that month. The **RI Fee** initially is added to your bill on the day of purchase and on the first day of each billing period thereafter.
The **RI Fee** is calculated by multiplying your discounted hourly rate and the number of hours in the month.
The following table shows how the recurring monthly charges appear in the report.
| | |
| --- |--- |
| lineItem/LineItemType | RI fee |
| lineItem/ProductCode | AmazonEC2 |
| lineItem/UsageStartDate | 2016-01-01T00:00:00Z |
| lineItem/UsageType | HeavyUsage: m4.large |
| lineItem/LineItemDescription | USD 0.0309 hourly fee per Linux/UNIX (Amazon VPC), m4.large instance |
| lineItem/NormalizationFactor | 4 |
| lineItem/UnblendedCost | 23 |
| Reservation/AvailabilityZone | |
| Reservation/ReservationARN | arn:aws:ec2:us-east-1:123456789012:reserved-instances/f8c204c1-dd48-43f1-adb8-f88aa61e0dea |
| Reservation/TotalReservedunits | 744 |
| Reservation/TotalReservedNormalizedUnits | 2976 |
Recurring monthly charges are recorded differently for RIs that have an Availability Zone or AWS Region Region scope. For RIs that have an Availability Zone scope, the corresponding Availability Zone is shown in the **reservation/AvailabilityZone** column. For RIs that have a Region scope, the **reservation/AvailabilityZone** column is empty. RIs with a Region scope have values for the **lineitem/NormalizationFactor** and **reservation/TotalReservedNormalizedUnits** columns that show the instance size.
**Note**
The recurring RI fee is calculated differently than the SavingsPlanRecurringFee. The recurring RI fee is a monthly charge while the SavingsPlanRecurringFee is an hourly charge. For information on the SavingsPlanRecurringFee, see [Understanding Savings Plans](cur-sp.md).
## RI discount benefits
The **Discounted Usage** line item describes the instance usage that received a matching RI discount benefit, and is added to your bill when you have usage that matches one of your RIs. AWS calculates RI discount benefits based on matching usage: for example, the use of an instance that matches the instance reservation. If you have matching usage, the cost associated with the usage line item is always zero because the charges associated with RIs are already accounted for in the two other line items (the upfront fee and the recurring monthly charges).
The following table shows an example of usage that received an RI discount benefit.
| | |
| --- |--- |
| lineItem/LineItemType | DiscountedUsage |
| lineItem/ProductCode | AmazonEC2 |
| lineItem/UsageStartDate | 2016-01-01T00:00:00Z |
| lineItem/UsageType | BoxUsage:m4.large |
| lineItem/LineItemDescription | Linux/UNIX (Amazon VPC), m4.large Reserved Instance applied |
| lineItem/ResourceId | i-1bd250bc |
| lineItem/AvailabilityZone | us-east-1b |
| lineItem/NormalizationFactor | 4 |
| lineItem/NormalizedUsageAmount | 4 |
| lineItem/UnblendedRate | 0 |
| lineItem/UnblendedCost | 0 |
| Reservation/ReservationARN | arn:aws:ec2:us-east-1:123456789012:reserved-instances/f8c204c1-dd48-43f1-adb8-f88aa61e0dea |
The value for **UsageAmount** in the Amazon EC2 **DiscountedUsage** line is the actual number of hours used. The value for **NormalizedUsageAmount** is the value for **UsageAmount** multiplied by the value for **NormalizationFactor**. The value for **NormalizationFactor** is determined by the instance size. When an RI benefit discount is applied to a matching line item of usage, the Amazon Resource Name (ARN) value in the **reservation/ReservationARN** column for the initial upfront fees and recurring monthly charges matches the ARN value in the discounted usage line items.
For more information about mapping instance size to normalization factor, see [ Support for modifying instance sizes](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ri-modification-instancemove.html) in the *Amazon EC2 User Guide*.
## Reserved Instance type
To determine if your report line items are associated with a Standard Reserved Instance or a Convertible Reserved Instance, filter the **lineItem/LineItemType** column by **Fee** or **RI fee**. Then, review the **product/OfferingClass** column, which indicates the Reserved Instance type.
To determine if your report line items are associated with a zonal or regional Reserved Instance, review the **reservation/AvailabilityZone** column. For zonal Reserved Instances, this column shows the corresponding Availability Zone. For regional Reserved Instances, this column is empty.
## Reserved Instance benefits applied to instance usage
To understand which instance usage line items benefitted from which Reserved Instances, you can filter your report by one or more of the following columns:
+ **reservation/reservationARN**: Filter this column by a reservation ARN to identify which Reserved Instance lease is associated with each line item.
+ **lineitem/ResourceId**: Review this column for the ID of the resource that's covered by the Reserved Instance.
+ **lineitem/LineItemType**: Filter this column by **Fee**, **RI fee**, or **DiscountedUsage** to determine the associated fees or benefits.
+ **lineitem/UsageType**: Filter this column by **HeavyUsage** to identify **RI fee** line items. Or, filter this column by **BoxUsage** to identify **DiscountedUsage** line items.
+ **lineitem/UsageAmount**: For **RI fee** line items, this column shows the total number of hours in the month that the Reserved Instance was applied. For **DiscountedUsage** line items, this column shows the total number of hours that the Reserved Instance was applied to a specific instance at the daily or monthly level, depending on how you configured your report.
To understand a size flexible Reserved Instance’s number of normalized units applied to instance usage, review the **lineitem/NormalizedUsageAmount** column in your report. The value in this column equals the product of the following columns:
+ **lineitem/UsageAmount**: This column shows the metered instance usage measured in hours.
+ **lineItem/NormalizationFactor**: For **DiscountedUsage** and **RI fee** line items, this column shows the associated normalization factor of the instance. For more information on the normalization factor, see [Instance size flexibility determined by normalization factor](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/apply_ri.html#ri-normalization-factor) in the *Amazon EC2 User Guide*.
For AWS Organizations with multiple accounts, to see which accounts purchased or benefitted from a Reserved Instance, review the following columns:
+ **reservation/reservationARN**: Review the reservation ARNs to see which accounts purchased the Reserved Instance. The ARN includes the account ID.
+ **lineitem/UsageAccountId**: For **DiscountedUsage** line items, this column identifies the account IDs that received benefits from the purchased Reserved Instances.
**Note**
A Reserved Instance is a billing subscription and not a resource like an Amazon EC2 instance. Because of this, Reserved Instances that are tagged don't populate line items like a tagged resource. For line items with **DiscountedUsage**, tags populate for the tagged resources and not for the Reserved Instance.
To identify costs associated with a specific Reserved Instance lease, you can filter **Fee** or **RI fee** line items by the Reserved Instance ARN, which is the lease ID. To organize your cost data for Reserved Instances, consider using AWS Cost Categories. For more information, see [Managing your costs with AWS Cost Categories](https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/manage-cost-categories.html) in the *AWS Billing User Guide*
# Understanding your amortized reservation data
Amortizing is when you distribute one-time reservation costs across the billing period that is affected by that cost. Amortizing enables you to see your costs in accrual-based accounting as opposed to cash-based accounting. For example, if you pay \$1365 for an All Upfront RI for one year and you have a matching instance that uses that RI, that instance costs you \$11 a day, amortized.
You can see the data that Billing and Cost Management uses to calculate your amortized costs in the following Cost and Usage Reports columns.
**Topics**
+ [Reserved Instance inventory](#ri-inventory)
+ [Amortization data for the billing period](#amortization-billing-period)
+ [Reserved Instance effective costs](#ri-effective-costs)
**Note**
Not all **reservation/** columns are populated for every Reserved Instance line item. The **reservation/** columns in your report are populated based on the line item type. For example, **RI fee** line items populate the **reservation/UnusedAmortizedUpfrontFeeForBillingPeriod** column. Meanwhile, **DiscountedUsage** line items populate the **reservation/effectivecost** column.
## Reserved Instance inventory
You can use the following columns to track your RI inventory. The values for these columns appear only for RI subscription line items (also known as `RI Fee` line items) and not for the actual instances using the RIs.
For more information about column descriptions and sample values, see [Reservation details](reservation-columns.md).
+ reservation/UpfrontValue
+ reservation/startTime
+ reservation/endTime
+ reservation/modificationStatus
## Amortization data for the billing period
You can use the following columns to understand the amortized costs of your RIs for the billing period. The values for these columns appear only for RI subscription line items (also known as `RI Fee` line items) and not for the actual instances using the RIs.
For more information about column descriptions and sample values, see [Reservation details](reservation-columns.md).
+ reservation/amortizedUpfrontFeeForBillingPeriod
+ reservation/unusedQuantity
+ reservation/unusedNormalizedUnitQuantity
+ reservation/unusedRecurringFee
+ reservation/unusedAmortizedUpfrontFeeForBillingPeriod
## Reserved Instance effective costs
You can use the following columns to understand your effective cost at the instance level. The values for these columns appear only for instance usage line items (also known as `Discounted Usage boxUsage` line items).
For more information about column descriptions and sample values, see [Reservation details](reservation-columns.md).
+ reservation/amortizedUpfrontCostForUsage
+ reservation/recurringFeeForUsage
+ reservation/effectiveCost
# Monitoring your size flexible reservations for Amazon EC2
Amazon EC2 Reserved Instances that apply to a Region provide Availability Zone flexibility and instance size flexibility. Reserved Instances that provide Availability Zone flexibility provide a discount on usage in any Availability Zone in the Region. Reserved Instances that provide instance size flexibility provide a discount on usage, regardless of instance size in that family. Size flexible Reserved Instances apply to the smallest instance sizes first. For more information, see [How Reserved Instances are applied](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/apply_ri.html) in the *Amazon EC2 User Guide*.
To understand how instance size flexibility provided by your Reserved Instance is applied to your usage, refer to the **lineItem/NormalizationFactor** and **lineItem/NormalizedUsageAmount** columns.
**Note**
Instance size flexibility is supported only by Linux or Unix Reserved Instances with default tenancy that are assigned to a Region. For more information on the limitations of instance size flexibility for Regional Reserved Instances, see [How regional Reserved Instances are applied ](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/apply_ri.html#apply-regional-ri) in the *Amazon EC2 User Guide*.
In a Cost and Usage Report, the Reserved Instance usage is applied by default to the account that purchased the Reserved Instance. Any available Reserved Instance benefit that the purchasing account can’t use within the hour is then applied to other linked accounts based on the available matching On-Demand Instance usage.
## Example
You purchase one `m4.xlarge` RI in a given Region. This `m4.xlarge` RI can be applied automatically to all `m4` instance usage in the same Region. In the following table, AWS applied the `m4.xlarge` to two separate `m4.large` instances.
| | | | |
| --- |--- |--- |--- |
| lineItem/LineItemType | RIFee | Discounted Usage | Discounted Usage |
| lineItem/ProductCode | AmazonEC2 | AmazonEC2 | AmazonEC2 |
| lineItem/UsageStartDate | 2016-01-01T00:00:00Z | 2016-01-01T00:00:00Z | 2016-01-01T00:00:00Z |
| lineItem/UsageType | HeavyUsage:m4.xlarge | BoxUsage:m4.large | BoxUsage:m4.large |
| lineItem/LineItemDescription | USD 0.0618 hourly fee per Linux/UNIX (Amazon VPC), m4.xlarge instance | Linux/UNIX (Amazon VPC), m4.large Reserved Instance applied | Linux/UNIX (Amazon VPC), m4.large Reserved Instance applied |
| lineItem/ResourceId | | i-1bd250bc | i-1df340ed |
| lineItem/UsageAmount | | 1 | 1 |
| lineItem/NormalizationFactor | 4 | 4 | 4 |
| lineItem/NormalizedUsageAmount | | 4 | 4 |
| lineItem/UnblendedRate | | 0 | 0 |
| lineItem/UnblendedCost | 46 | 0 | 0 |
| Reservation/ ReservationARN | arn:aws:ec2:us-east-1: 123456789012:reserved-instances /f8c204c1 | arn:aws:ec2:us-east-1: 123456789012:reserved-instances /f8c204c1 | arn:aws:ec2:us-east-1: 123456789012:reserved-instances /f8c204c1 |
| Reservation/TotalReservedUnits | 744 | | |
| Reservation/TotalReserved NormalizedUnits | 5952 | | |
The two `m4.large` usage line items have different **ResourceId**s, and both received a discount benefit from the single `m4.xlarge` RI. This is shown by matching the **reservationARN** value across the usage and recurring monthly charge line items.
For more information about RI purchase options, see [How you are billed](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts-reserved-instances-application.html#reserved-instances-payment-options) in the *Amazon EC2 User Guide*.
# Monitoring your On-Demand capacity reservations
Capacity reservations enable you to reserve capacity for your Amazon EC2 instances for any duration in a specific Availability Zone. This enables you to create and manage capacity reservations separately from the billing discounts offered by Regional Reserved Instances (RI). To benefit from billing discounts, you can use Regional RIs in combination with capacity reservations.
## Capacity reservation line items
You can use some columns defined in the AWS CUR data dictionary to track your capacity reservations. The following columns are also used for capacity reservations.
This section defines these line items with supplementary definitions specific to capacity reservations.
For more information about Cost and Usage Reports column descriptions, see [Line item details](Lineitem-columns.md).
A \$1 [B](#lcr-B) \$1 C \$1 D \$1 E \$1 F \$1 G \$1 H \$1 I \$1 J \$1 K \$1 L \$1 M \$1 N \$1 O \$1 P \$1 Q \$1 [R](#lcr-R) \$1 S \$1 T \$1 [U](#lcr-U) \$1 VWXYZ
### B
#### lineItem/BlendedRate
For capacity reservations with a **UsageType** of **Reservation** or **DedicatedRes**, the **BlendedRate** is `0`. This is because the capacity reservation costs are associated with the instance that provides the capacity, instead of with the capacity reservation itself.
### R
#### lineItem/ResourceId
If you included `lineItem/ResourceId` when you created your Cost and Usage Reports, you can identify and track your capacity reservations using the **ResourceId** column. The capacity reservation **ResourceId** is captured only for the **UnusedBox,** **UnusedDed**, **Reservation**, and **DedicatedRes** **UsageTypes**.
Capacity reservations always include a `cr-` in their resource ID, and the resource ID has the following format:
```
arn:aws:ec2:::/cr-0be443example1db6f
```
### U
#### lineItem/UnblendedCost
The `BlendedRate` multiplied by the `UsageAmount`.
#### lineItem/UnblendedRate
For capacity reservations with a **UsageType** of **Reservation** or **DedicatedRes**, the **UnblendedRate** is `0`. This is because the costs for capacity reservations are associated with the instance that provides the capacity, instead of with the capacity reservation itself.
#### lineItem/UsageAmount
How much of a capacity reservation you've used. Each capacity reservation can have multiple slots for an hour, enabling you to run more than one instance that uses the reservation during an hour. Therefore, it's possible to use more than one instance-hour in an hour. **UsageAmount** is calculated by multiplying the number of instance slots covered by the line item with the number of hours covered by the line item.
#### lineItem/UsageType
How much of a specific reservation you've used. For Amazon EC2, the options are as follows:
##### lineItem/lineitemtype = BoxUsage
For this `UsageType`, the `UsageAmount` column is the amount of instance-hours of an instance you've used.
For example, a report covers 1 hour and has a capacity reservation line item that can cover 10 instances. If you use two instance-slots during the time period covered by the report, the **BoxUsage** **UsageAmount** covers the number of instance hours that you reserved and used. In this case, this is two (the number of used instance slots) multiplied by 1 hour (the time covered by the report) for a total of two. For a report that covers 1 day, the **UsageAmount** is two multiplied by 24, for a total of 48.
##### DedicatedRes
For a **UsageType** of **DedicatedRes**, the **UsageAmount** column describes how many instance-hours of a dedicated capacity reservation you reserved.
##### Reservation
For a **UsageType** of **Reservation**, the **UsageAmount** column describes how many instance-hours of a capacity reservation you reserved.
For example, if a report covers one hour and has a capacity reservation line item that can cover 10 instances, the **Reservation** **UsageAmount** covers the number of instance slots that you reserved. In this case, that's 10 (the number of available instance slots) multiplied by 1 hour (the time covered by the report) for a total of 10. For a report that covers 1 day, the **UsageAmount** would be 10 multiplied by 24, for a total of 240.
##### UnusedBox
For a **UsageType** of **UnusedBox**, the **UsageAmount** column describes how many instance-hours of a capacity reservation you reserved, but didn't use.
For example, a report covers 1 hour and has a capacity reservation line item that can cover 10 instances. If you didn't use eight instance-slots during the time period covered by the report, the **UnusedBox** **UsageAmount** covers the number of instance hours that you reserved but didn't use. In this case, that's eight (the number of unused instance slots) multiplied by 1 hour (the time covered by the report) for a total of eight. For a report that covers 1 day, the **UsageAmount** is eight multiplied by 24, for a total of 192.
##### UnusedDed
For a **UsageType** of **UnusedDed**, the **UsageAmount** column describes how many instance-hours of a dedicated capacity reservation that you reserved, but didn't use.