Effective March 1st, regional RIs now provide instance size flexibility, in addition to AZ flexibility. With instance size flexibility, your regional RI’s discounted rate will automatically apply to usage of any size in the instance family, and in any AZ. Let’s say you own an m4.2xlarge Linux/UNIX regional RI in US East (N.Virginia). The discounted rate of this RI can automatically apply to 2 m4.xlarge instances in us-east-1a or 4 m4.large instances in us-east-1b without you needing to do anything. Since the discounted rate is automatically applied to usage irrespective of size or AZ, you can save even more off your EC2 bill with no management overhead of trying to match RI discounts to running instances. With the instance size flexibility and AZ flexibility provided by regional RIs, customers no longer have to worry about being tied to a specific size or AZ, or worry about launching the right instance size in the right AZ to match their RIs. This helps you save time and money, and lets you focus on the performance and needs of your application.

