Cost Estimation

Purpose

Estimate infrastructure costs, operational expenses, and total cost of ownership to support budget planning and architecture decisions.

When to Use

• Architecture planning
• Budget approval
• Scaling decisions
• Cost optimization
• Vendor comparison

Prerequisites

• Infrastructure design defined
• Expected usage patterns
• Cloud provider pricing
• Operational requirements

Process

Step 1: Identify Cost Components

Categories:
- Compute (VMs, containers, serverless)
- Database (instances, storage, backup)
- Storage (object, block, backup)
- Network (transfer, CDN, load balancer)
- Third-party services
- Licenses
- Operational (monitoring, logging)

Step 2: Estimate Usage

For each component:
- Baseline usage
- Growth rate
- Peak vs normal
- Seasonal variation

Step 3: Calculate Costs

For each component:
- Unit cost (from pricing)
- Estimated units
- Monthly cost
- Annual cost
- Growth projection

Step 4: Consider Optimizations

Cost reduction options:
- Reserved instances
- Spot instances
- Right-sizing
- Auto-scaling
- Caching
- CDN
- Storage tiers

Step 5: Create Cost Model

Model includes:
- Itemized costs
- Monthly totals
- Annual projections
- Growth scenarios
- Optimization opportunities

Inputs

Input	Type	Required	Description
infrastructure_design	Markdown	Yes	Architecture
usage_projections	JSON	Yes	Expected usage
pricing	JSON	Optional	Provider pricing

Outputs

Output	Type	Description
cost_estimate.md	Markdown	Detailed estimate
cost_model.xlsx	Spreadsheet	Calculations
optimization_recommendations	Markdown	Cost savings

StudyAbroad-Specific Considerations

• Document storage grows linearly
• Peak costs during deadline periods
• External API costs (if metered)
• GDPR compliance may add costs

Integration Points

• DevOps Agent: Infrastructure implementation
• Operations Agent: Cost monitoring

Examples

Cost Estimate - StudyAbroad-v1 (AWS, EU-WEST-1)

MONTHLY COST BREAKDOWN:

COMPUTE:
| Component | Spec | Qty | Monthly |
|-----------|------|-----|---------|
| API (ECS) | 0.5 vCPU, 1GB | 2-10 | $80-400 |
| Workers | 0.5 vCPU, 1GB | 1-5 | $40-200 |
| Average | | | $180 |

DATABASE:
| Component | Spec | Qty | Monthly |
|-----------|------|-----|---------|
| RDS PostgreSQL | db.t3.medium | 1 | $100 |
| RDS Storage | 100GB | 1 | $25 |
| Read Replica | db.t3.small | 1 | $50 |
| Backup | 100GB | 1 | $10 |
| Total | | | $185 |

CACHE:
| Component | Spec | Monthly |
|-----------|------|---------|
| ElastiCache | cache.t3.micro | $15 |

STORAGE:
| Component | Spec | Monthly |
|-----------|------|---------|
| S3 (documents) | 500GB | $12 |
| S3 (requests) | 1M req | $5 |
| CloudFront | 100GB transfer | $10 |
| Total | | $27 |

NETWORK:
| Component | Monthly |
|-----------|---------|
| ALB | $20 |
| Data Transfer | $30 |
| Total | $50 |

OTHER:
| Component | Monthly |
|-----------|---------|
| Secrets Manager | $5 |
| CloudWatch | $20 |
| Route53 | $5 |
| Total | $30 |

SUMMARY:
| Category | Monthly | Annual |
|----------|---------|--------|
| Compute | $180 | $2,160 |
| Database | $185 | $2,220 |
| Cache | $15 | $180 |
| Storage | $27 | $324 |
| Network | $50 | $600 |
| Other | $30 | $360 |
| TOTAL | $487 | $5,844 |

With reserved instances (1yr): ~$4,200/year
Peak months (add 50%): ~$730/month

GROWTH PROJECTION:
| Year | Users | Monthly Cost |
|------|-------|--------------|
| Y1 | 5K | $500 |
| Y2 | 15K | $800 |
| Y3 | 30K | $1,200 |

Validation

• All components included
• Pricing is current
• Usage estimates reasonable
• Growth scenarios modeled
• Optimization identified