AWS Savings Plans vs Reserved Instances: Which Saves More?

Both Savings Plans and Reserved Instances (RIs) reward you for committing to steady usage with discounts up to ~72% off on-demand. They get there differently, and choosing well comes down to how predictable your workloads are.

How Reserved Instances work

An RI is a commitment to a specific instance configuration — family, size, region, and sometimes OS/tenancy — for a 1- or 3-year term. Standard RIs give the deepest discount but are rigid; Convertible RIs trade some discount for the ability to exchange them for other types. The catch: if your usage shifts away from what you reserved, the discount can go unused.

How Savings Plans work

A Savings Plan is a commitment to spend a fixed dollar amount per hour (for example, $5/hour) for 1 or 3 years, rather than to a specific instance. Two flavors:

• Compute Savings Plans — the most flexible. The discount applies automatically across instance families, sizes, regions, OS, and even Fargate and Lambda. Up to ~66% off.
• EC2 Instance Savings Plans — locked to an instance family in a region, for a deeper discount (up to ~72%), but less flexibility.

Side by side

Which should you choose?

For most teams, Compute Savings Plans are the best default: nearly the same discount as RIs without the risk of stranded commitments when your architecture evolves. Reach for EC2 Instance Savings Plans or Standard RIs only for large, stable, well-understood baselines where the extra few points of discount outweigh the lost flexibility.

The golden rule: cover the baseline, not the peaks

Commit only to the floor of your usage — the amount you're confident runs no matter what — and leave the variable top on on-demand. Over-committing locks you into spend you may not use, which erases the savings.

CloudWireHub measures your steady-state usage and recommends a commitment level that captures the savings without overcommitting — see your number for free.