Regional and zonal Reserved Instances - Amazon EC2 Reserved Instances and Other AWS Reservation Models
Differences between regional and zonal Reserved InstancesLimitations for instance size flexibility

Regional and zonal Reserved Instances

When you purchase a Reserved Instance, you determine the scope of the Reserved Instance. The scope is either regional or zonal.

  • Regional: When you purchase a Reserved Instance for a Region, it's referred to as a regional Reserved Instance.

  • Zonal: When you purchase a Reserved Instance for a specific Availability Zone, it's referred to as a zonal Reserved Instance.

Differences between regional and zonal Reserved Instances

The following table highlights some key differences between regional Reserved Instances and zonal Reserved Instances:

Table 2 – Comparison of regional and zonal Reserved Instances

Regional Reserved Instances Zonal Reserved Instances
Availability Zone flexibility The Reserved Instance discount applies to instance usage in any Availability Zone in the specified Region. No Availability Zone flexibility—the Reserved Instance discount applies to instance usage in the specified Availability Zone only.
Capacity reservation No capacity reservation—a regional Reserved Instance does not provide a capacity reservation. A zonal Reserved Instance provides a capacity reservation in the specified Availability Zone.
Instance size flexibility The Reserved Instance discount applies to instance usage within the instance family, regardless of size. Only supported on Amazon Linux/Unix Reserved Instances with default tenancy. For more information, see Instance size flexibility determined by normalization factor. No instance size flexibility—the Reserved Instance discount applies to instance usage for the specified instance type and size only.

Limitations for instance size flexibility

Instance size flexibility does not apply to the following Reserved Instances:

  • Reserved Instances that are purchased for a specific Availability Zone (zonal Reserved Instances)

  • Reserved Instances with dedicated tenancy

  • Reserved Instances for Windows Server, Windows Server with SQL Standard, Windows Server with SQL Server Enterprise, Windows Server with SQL Server Web, RHEL, and SUSE Linux Enterprise Server

  • Reserved Instances for G4ad, G4dn, G5, and G5g instances.