Alright 😄 — let’s break down all AWS Savings Plans and compare them so it’s crystal clear which one is best for your case.
We’ll compare Compute Savings Plans, EC2 Instance Savings Plans, and Reserved Instances.
1. AWS Savings Plans — Overview
AWS offers two main types of Savings Plans:
| Savings Plan | Coverage | Flexibility | Savings (%) | Use Cases |
|---|---|---|---|---|
| Compute Savings Plan | Applies to any EC2 instance, Fargate, and Lambda | High flexibility (any region, instance type, OS, tenancy) | Up to ~66% | Best for mixed workloads across EC2, Fargate, Lambda |
| EC2 Instance Savings Plan | Applies to a specific instance family in a region | Medium flexibility (change AZ, OS, size within family) | Up to ~72% | Good for predictable workloads on EC2 only |
| Reserved Instances | Applies to specific instance types and regions | Low flexibility (fixed instance type) | Up to ~75% | Good for highly predictable workloads and steady capacity needs |
2. Detailed Comparison
| Feature | Compute Savings Plan | EC2 Instance Savings Plan | Reserved Instances |
|---|---|---|---|
| Coverage | EC2, Fargate, Lambda | EC2 only | EC2 only |
| Instance Flexibility | Any instance type, OS, region | Specific family in region | Specific type |
| Region Flexibility | Yes | Yes (within family) | No |
| OS Flexibility | Yes | Yes | No |
| Capacity Reservation | No | No | Optional |
| Commitment Term | 1 or 3 years | 1 or 3 years | 1 or 3 years |
| Payment Options | All Upfront, Partial Upfront, No Upfront | All Upfront, Partial Upfront, No Upfront | All Upfront, Partial Upfront, No Upfront |
| Savings Range | Up to ~66% | Up to ~72% | Up to ~75% |
| Best for | Mixed workloads, Fargate/Lambda | Predictable EC2 workloads | Predictable EC2 workloads with fixed capacity |
3. Why Compute Savings Plans are Best for Mixed EC2, Fargate, Lambda
In your case:
- Front-end → Fargate
- API layer → Lambda
- Data ingestion → EC2 (spot)
Since EC2 Instance Savings Plans and Reserved Instances only apply to EC2, they wouldn’t cover Fargate or Lambda.
The Compute Savings Plan covers all three services — that means maximum savings with one commitment.
4. Savings Example
Let’s imagine a case where you have:
- EC2 → $1,000/month
- Fargate → $500/month
- Lambda → $200/month
Total monthly cost = $1,700.
| Plan Type | Monthly Cost | Savings Estimate |
|---|---|---|
| On-Demand | $1,700 | — |
| EC2 Instance Savings | $1,360 | ~20% savings |
| Compute Savings Plan | $1,200 | ~30% savings |
| Reserved Instances | $1,275 | ~25% savings |
✅ Compute Savings Plan gives the best coverage and cost savings for your mix of services.
📌 Key takeaway:
For mixed compute workloads (EC2 + Fargate + Lambda), Compute Savings Plans are almost always the best cost optimization strategy.
