Compare EC2 Reserved Instances and Savings Plans

Why this is worth a look

AWS recommends Savings Plans over Reserved Instances and describes them as more flexible. A Savings Plan commitment is measured in USD per hour. Compute Savings Plans apply across eligible EC2 families, sizes, Regions, operating systems and tenancy, and also apply to Fargate and Lambda. EC2 Instance Savings Plans commit to a family in a chosen Region, while allowing size, OS and tenancy changes within that family and Region. An RI is a billing discount for matching On-Demand usage. Regional and zonal RIs differ in capacity and Availability Zone behavior. AWS documents one-year and three-year RI terms. Its Savings Plans examples show one-year partial-upfront commitments, so verify the exact Savings Plans offer rather than assuming RI parity.

Complete this read-only worksheet manually using measured hourly usage and the exact AWS offerings under review. It covers matching, capacity, term and payment assumptions without changing resources.

Execution surface: manual worksheet. No account access, API calls, permissions, or resource changes.
Scope: EC2 usage by Region, family, size, platform and tenancy, plus eligible Fargate and Lambda usage.
Units and window: record recurring USD/hour usage from completed billing periods, including peaks, weekends and seasonal lows.

Workload
[ ] Record hourly usage by Region, instance family and size, platform and tenancy.
[ ] Separate usage covered by existing RIs before evaluating Savings Plans.
[ ] Record eligible Fargate or Lambda usage for a Compute Savings Plan.
[ ] Mark likely changes in family, Region, platform, tenancy or service.

Capacity and matching
[ ] State whether capacity in one specified Availability Zone is required.
[ ] For an RI, verify instance type, Region, tenancy, platform and regional or zonal scope.
[ ] For an EC2 Instance Savings Plan, verify family and chosen Region.
[ ] For a Compute Savings Plan, verify eligible EC2, Fargate or Lambda usage.

Commercial review
[ ] Compare the documented one-year and three-year RI terms.
[ ] Compare RI All Upfront, Partial Upfront and No Upfront options.
[ ] For a Savings Plan, record the exact term, payment option and USD/hour commitment shown in AWS.
[ ] Choose a commitment supported by recurring eligible usage after RI coverage is applied.
[ ] Document an owner for utilization review through the full term.

How to confirm it

1. 01

   Measure recurring hourly usage

   Use completed billing periods that include peaks, weekends and seasonal lows. Record the recurring eligible USD/hour floor, and apply existing RI coverage before sizing a Savings Plan because AWS applies RIs first.

2. 02

   Map expected workload changes

   Record possible changes across instance families, Regions, operating systems, tenancy, Fargate and Lambda. Compute Savings Plans cover broader eligible changes, while EC2 Instance Savings Plans remain tied to a family and chosen Region.

3. 03

   Separate discount from capacity

   A regional RI does not reserve capacity. A zonal RI reserves capacity in its specified Availability Zone and applies only there, so treat the capacity requirement as a separate decision from discount flexibility.

4. 04

   Review terms and payment options

   For RIs, compare one-year or three-year terms and All Upfront, Partial Upfront or No Upfront options. For Savings Plans, record the exact term, payment option and USD/hour commitment offered in AWS. Do not assume the RI choices apply to Savings Plans.

5. 05

   Verify matching attributes

   Before approval, confirm the Reserved Instance offering and matching attributes in AWS. Check instance type, Region, tenancy, platform and regional or zonal scope for an RI, and family plus chosen Region for an EC2 Instance Savings Plan.

Primary sources