AWS Cost Estimator

Estimate monthly costs for AWS resources using the AWS Pricing API — a REST API that returns real AWS retail pricing data.

When to Use

• During CloudFormation template generation to show cost estimates before deployment
• When user asks "how much will this cost?" or "estimate costs"
• To compare cost of different instance types or service tiers
• To validate budget constraints before deployment

API Reference

Endpoint: https://pricing.us-east-1.amazonaws.com/offers/v1.0/aws/{SERVICE}/current/index.json

Alternative (Bulk Price List API):

GET https://pricing.us-east-1.amazonaws.com/offers/v1.0/aws/AmazonEC2/current/{region}/index.json

Key facts:

• No authentication required for public pricing pages
• Prices are in USD by default
• Use the AWS Pricing Calculator for complex scenarios: https://calculator.aws/
• Always note the retrieval date in estimates

Procedure

1. Parse CloudFormation Template Resources

Extract from the CloudFormation template:

• Resource type (AWS::EC2::Instance, AWS::RDS::DBInstance, etc.)
• Instance/class size (e.g., t3.micro, db.t3.medium)
• Region (from template parameter or default)
• Storage sizes and types
• Any quantity-affecting properties

2. Map Resource Types to Pricing

Use the AWS Pricing API or well-known current rates for common services.

Query pattern using AWS CLI:

# Get pricing for EC2 instances
aws pricing get-products \
  --service-code AmazonEC2 \
  --filters \
    "Type=TERM_MATCH,Field=instanceType,Value=t3.micro" \
    "Type=TERM_MATCH,Field=operatingSystem,Value=Linux" \
    "Type=TERM_MATCH,Field=location,Value=US East (N. Virginia)" \
    "Type=TERM_MATCH,Field=tenancy,Value=Shared" \
    "Type=TERM_MATCH,Field=preInstalledSw,Value=NA" \
    "Type=TERM_MATCH,Field=capacityStatus,Value=Used" \
  --region us-east-1 \
  --query 'PriceList[0]' --output text | python3 -c "
import sys, json
data = json.loads(sys.stdin.read())
for term in data['terms']['OnDemand'].values():
    for price_dim in term['priceDimensions'].values():
        print(f\"{price_dim['description']}: \${price_dim['pricePerUnit']['USD']}/hr\")
"

Resource Type Mapping

EC2 Instances (AWS::EC2::Instance)

Service code: AmazonEC2

Unit: Per hour → multiply by 730 for monthly estimate.

Common instance pricing (us-east-1, Linux, On-Demand):

EBS Volumes (AWS::EC2::Volume)

Service code: AmazonEC2

S3 Buckets (AWS::S3::Bucket)

Service code: AmazonS3

• Standard storage: ~$0.023/GB/month
• Intelligent-Tiering (frequent): ~$0.023/GB/month
• Standard-IA: ~$0.0125/GB/month
• Glacier Instant: ~$0.004/GB/month
• PUT/POST requests: ~$0.005/1,000 requests
• GET requests: ~$0.0004/1,000 requests

Note: No fixed monthly cost — estimate based on expected data volume.

RDS Instances (AWS::RDS::DBInstance)

Service code: AmazonRDS

Plus: Storage at ~$0.115/GB/month (gp2) or ~$0.115/GB/month (gp3 base)

Lambda Functions (AWS::Lambda::Function)

Service code: AWSLambda

Consumption plan pricing:

• First 1M requests/month: FREE
• Additional requests: $0.20 per 1M requests
• First 400,000 GB-seconds/month: FREE
• Additional GB-seconds: $0.0000166667 per GB-second

Example (128 MB, 500ms avg, 1M invocations/month):

• Compute: 1M × 0.5s × 0.125 GB × $0.0000166667 = ~$1.04
• Requests: $0.20
• Total: ~$1.24/month (first 1M invocations included)

DynamoDB Tables (AWS::DynamoDB::Table)

Service code: AmazonDynamoDB

• On-Demand: $1.25 per million write request units, $0.25 per million read request units
• Provisioned: $0.00065/WCU/hour, $0.00013/RCU/hour
• Storage: $0.25/GB/month
• PITR: $0.20/GB/month

ECS/Fargate Tasks (AWS::ECS::TaskDefinition)

Service code: AmazonECS

• vCPU: $0.04048/vCPU/hour
• Memory: $0.004445/GB/hour

Example (0.5 vCPU, 1 GB, running 730 hours/month):

• vCPU: 0.5 × $0.04048 × 730 = ~$14.78
• Memory: 1 × $0.004445 × 730 = ~$3.24
• Total: ~$18.02/month

EKS Clusters (AWS::EKS::Cluster)

• Control plane: $0.10/hour = ~$73/month (fixed)
• Worker nodes (EC2): priced as EC2 instances separately

Secrets Manager (AWS::SecretsManager::Secret)

• $0.40/secret/month
• $0.05 per 10,000 API calls

CloudWatch Logs

• Ingestion: $0.50/GB
• Storage: $0.03/GB/month
• Insights queries: $0.005/GB scanned

3. Calculate Monthly Costs

Apply the correct multiplier:

4. Handle Free Tier

Note any AWS Free Tier allowances (first 12 months or always free):

5. Present Cost Estimate

Format the output as a clear cost breakdown:

### 💰 Estimated Monthly Cost

| # | Resource | Type | SKU/Tier | Est. Monthly |
|---|----------|------|----------|-------------|
| 1 | MyWebServer | EC2 Instance | t3.medium (Linux) | $30.37 |
| 2 | MyWebServer OS Disk | EBS Volume | 20 GB gp3 | $1.60 |
| 3 | MyDatabase | RDS PostgreSQL | db.t3.medium Multi-AZ | $115.00 |
| 4 | MyDatabase Storage | RDS Storage | 100 GB gp3 | $11.50 |
| 5 | MyBucket | S3 Storage | Standard ~50 GB | $1.15 |
| 6 | MyFunction | Lambda | ~1M invocations | $0.20 |
| | | | **Total** | **$159.82/mo** |

**Notes:**
- Prices are AWS retail (pay-as-you-go) in USD for us-east-1
- Actual costs may vary with Reserved Instances, Savings Plans, or enterprise agreements
- Data transfer costs not included (first 100 GB/month outbound: $0.09/GB)
- Estimates based on 24/7 operation (730 hours/month)
- Prices current as of 2026-04-15 — verify at https://calculator.aws/

**Cost Optimization Opportunities:**
- 💡 EC2 1-Year Reserved Instance: ~40% savings on compute
- 💡 EC2 3-Year Reserved Instance: ~60% savings on compute
- 💡 RDS Reserved Instance (1-year): ~40% savings on database
- 💡 Use Savings Plans for flexible commitment discounts

6. Save Cost Estimate

Save the estimate to deployment artifacts:

File: .aws/deployments/{deployment-id}/cost-estimate.json

{
  "estimatedAt": "2026-04-15T00:00:00Z",
  "currency": "USD",
  "region": "us-east-1",
  "monthlyTotal": 159.82,
  "resources": [
    {
      "name": "MyWebServer",
      "type": "AWS::EC2::Instance",
      "sku": "t3.medium",
      "unitPrice": 0.0416,
      "unitOfMeasure": "1 Hour",
      "monthlyEstimate": 30.37
    }
  ],
  "notes": [
    "Retail pay-as-you-go pricing",
    "Data transfer not included"
  ],
  "source": "AWS Pricing API",
  "sourceUrl": "https://pricing.us-east-1.amazonaws.com"
}

Error Handling

If a price cannot be determined:

• Show ❓ Price not found with the resource type and instance size
• Link to the AWS Pricing Calculator: https://calculator.aws/
• Never fabricate a price — show Unknown and provide the manual lookup URL

If the API is unreachable:

• Fall back to a note: "Cost estimation unavailable — verify at https://calculator.aws/"
• Use the well-known rates table above for common resource types as a fallback estimate

Constraints

• DO NOT fabricate or guess prices — use the pricing table above or query the API
• DO NOT use hardcoded prices without noting they may be outdated
• ALWAYS show the pricing date so users know how current the estimate is
• ALWAYS note that actual costs may differ from retail pricing (Reserved Instances, Savings Plans, EDP)
• ALWAYS note that data transfer costs are not included in the estimate

References

• AWS Pricing Calculator
• AWS Pricing API
• EC2 Pricing
• RDS Pricing
• Lambda Pricing
• S3 Pricing
• DynamoDB Pricing
• Fargate Pricing