AWS offers Reserved Instances (RIs) and Savings Plans (SPs) as cost-saving options for long-term usage. While both options aim to reduce infrastructure costs, they differ in flexibility, coverage, and payment models. This article explains the key differences between RIs and SPs to help determine which option best suits your business needs.

• Flexibility and Coverage:
  • RIs: Specific to EC2 and related services such as Amazon RDS and Amazon ElastiCache, providing capacity reservation in a specific Availability Zone within a region.
  • SPs: Broader coverage across services, including EC2, Fargate, and Lambda, with no restriction to specific Availability Zones.
    
    
• Term Lengths and Commitments:
  • RIs: Commit to a specific instance for 1 or 3 years.
  • SPs: Commit to a 1-year or 3-year term without tying to a specific instance type, applying savings based on hourly usage.
    
    
• Payment Options:
  • RIs: Options for No Upfront, Partial Upfront, or All Upfront payments.
  • SPs: Options include All Upfront or No Upfront.
    
    
• Instance Size Flexibility:
  • RIs: Flexibility within the same instance family.
  • SPs: Greater flexibility across instance types and sizes, applying to eligible services.
    
    
• Coverage for New Services and Regions:
  • RIs: Limited to the services and regions available at the time of purchase.
  • SPs: Automatically applicable to newly eligible services and regions without additional actions.

Both Reserved Instances and Savings Plans provide meaningful cost savings for predictable workloads. Your choice should depend on the level of flexibility required and your specific AWS usage patterns.