AWS Savings Plans vs Reserved Instances: Which to Buy

For AWS Savings Plans vs Reserved Instances, the default answer is: buy a Savings Plan, not a Reserved Instance. The exception is OpenSearch, Redshift, and (until December 2025) databases, which still need the older Reserved model. That is the whole decision. For most teams a Compute Savings Plan is the right default: same discount as a Convertible Reserved Instance, far less to manage, and it follows your workload across instance families, regions, Fargate, and Lambda. The cases where a Reserved Instance still wins are narrow and specific, and the December 2025 launch of Database Savings Plans shrank them further. This post is the decision — RI vs Savings Plan, when each wins. It is not a deep-dive on how Savings Plans work under the hood; I cover the mechanics — how the $/hour commitment gets applied, the billing-hour math, the queue order against On-Demand — in a separate post. Here I only want to answer the question you actually have when the Cost Explorer recommendation pops up: which one do I buy? (Commitments are step three of a full bill audit — where they sit in the order is in what I'd audit first on a $50K AWS bill .) The short version Both Reserved Instances and Savings Plans are the same trade: you promise AWS a one- or three-year commitment, AWS gives you a discount over On-Demand. The difference is what you commit to . A Reserved Instance commits you to a specific instance configuration — family, and depending on type, size, region, OS, tenancy. A Savings Plan commits you to a dollar amount of usage per hour (e.g. "$10/hour of compute"), and AWS applies that discount to whatever matching usage you actually run. The Savings Plan is the more flexible instrument at the same discount level, which is why AWS itself now recommends Savings Plans over Reserved Instances for compute. ( AWS, Compute Savings Plans and Reserved Instances , accessed June 2026.) The Reserved Instance has not gone away — but for EC2 compute, it is mostly the legacy choice now. The d