Reserved Instance
A commitment-based discount on cloud compute in exchange for a 1- or 3-year term — typically 30–60% off on-demand pricing.
Updated 2026-04-22 · 3 min read
Definition
A Reserved Instance (RI) is a commitment to use a specific cloud instance configuration — family, size, region, tenancy — for 1 or 3 years in exchange for a discount off on-demand pricing. RIs predate Savings Plans and remain in wide use for database services (RDS, ElastiCache, Redshift) and workloads where instance shape is stable.
Why it matters
For predictable, long-lived workloads, RIs remain the cheapest commitment model on database and cache services. They're also the right tool when you know exactly which instance shape you'll run for the full term.
When to choose RI vs Savings Plans
- Pick RI for RDS / ElastiCache / Redshift (Savings Plans don't cover these), or when you need Convertible RIs for marketplace flexibility.
- Pick Savings Plans for EC2 / Fargate / Lambda when flexibility on instance family or region matters more than the last few points of discount.
Related Terms
Savings Plans
A flexible commitment discount covering a steady compute spend rate (USD/hr) across instance families, regions, and sometimes services.
Spot instances
Discounted cloud compute that can be reclaimed at short notice — ideal for fault-tolerant, interruptible workloads.
Right-sizing
Matching compute capacity to actual workload demand to eliminate over-provisioning.