# AvailableCapacityPerAvailabilityZone
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Contains the unused capacity of a DB capacity reservation in one Availability Zone.

This data type is used as a response element in the following operations:
+  `CancelDBCapacityReservation` 
+  `CreateDBCapacityReservation` 
+  `DescribeDBCapacityReservations` 
+  `ModifyDBCapacityReservation` 

## Contents
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**Note**  
In the following list, the required parameters are described first.

 ** AvailabilityZone **   
The name of the Availability Zone.  
Type: String  
Required: No

 ** AvailableCapacity **   
The number of DB instances that remain available in this Availability Zone. Amazon RDS decreases this value when a DB instance takes a unit of reserved capacity in this Availability Zone, and it increases this value when a DB instance releases that unit.  
A DB instance with a pending modification also holds a unit of reserved capacity. A DB instance has a pending modification when Amazon RDS accepts a change to the DB instance and applies that change later, during the maintenance window. Amazon RDS holds the unit from the time that it accepts the request. To find a DB instance with a pending modification, check `PendingModifiedValues` in the response of `DescribeDBInstances`.  
Amazon RDS reports available capacity only for a reservation that is in the `active` state and not past its end date. Otherwise, this value is `0`.  
Type: Integer  
Required: No

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\+\+](https://docs.aws.amazon.com/goto/SdkForCpp/rds-2014-10-31/AvailableCapacityPerAvailabilityZone) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/rds-2014-10-31/AvailableCapacityPerAvailabilityZone) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/rds-2014-10-31/AvailableCapacityPerAvailabilityZone)