Claude Code Models: Choose the Right AI for Every Task

Problem: Developers waste money using Claude Opus for everything, or struggle with Haiku when they need more power.

Quick Win: Set Sonnet 4 as your default model right now:

claude --model claude-sonnet-4-20250514

This saves 80% on costs while maintaining excellent performance for 90% of development tasks.

The Smart Model Strategy

Most developers make a costly mistake: using one model for everything. Claude Code offers four models, each optimized for different scenarios. Strategic switching can reduce your usage costs by 80% while improving performance.

Sonnet 4: Your Daily Driver

Best for: 90% of development work

# Set as default for balanced performance
export ANTHROPIC_MODEL="claude-sonnet-4-20250514"

Perfect for:

• Feature implementation and bug fixes
• Code reviews and refactoring
• API integration and database work
• Writing tests and documentation

Why Sonnet 4 wins: 90% of Opus capability at 2x the speed, rarely hits usage limits, ideal for pair programming workflow.

Opus: The Heavy Hitter

When to upgrade: Complex architectural decisions only

# Switch to Opus for complex analysis
claude --model claude-opus-4-20250514 --max-turns 20

Use Opus for:

• Large-scale refactoring across multiple systems
• Complex debugging with intricate dependencies
• Architectural decisions requiring deep reasoning
• Advanced security reviews

Cost reality: 5x more expensive than Sonnet, but justified for tasks requiring maximum reasoning power.

Haiku: The Speed Demon

When to downgrade: Simple, repetitive tasks

# Fast and cheap for basic operations
claude --model claude-3-5-haiku-20241022

Perfect for:

• Simple file reads and formatting
• Basic syntax validation
• Quick status checks
• Text transformations

Warning: Don't use Haiku for actual development. It struggles with complex logic and multi-file projects.

Tactical Model Switching

The ClaudeFast approach: Start with Sonnet, escalate when needed.

During Development Sessions

# Start your session with Sonnet 4
claude --model claude-sonnet-4-20250514
 
# Switch to Opus for complex refactoring
/model claude-opus-4-20250514
 
# Back to Sonnet for regular work
/model claude-sonnet-4-20250514

Cost Optimization Pattern

1. Default: Sonnet 4 for all standard development
2. Escalate: Switch to Opus only when Sonnet struggles
3. Delegate: Use Haiku for simple file operations
4. Monitor: Track usage to optimize model selection

This approach can reduce costs by 60-80% compared to using Opus for everything.

Model Selection by Task Type

Code Analysis Speed Rankings

1. Haiku: Instant but shallow analysis
2. Sonnet 3.5: Fast with good depth
3. Sonnet 4: Fast with excellent depth
4. Opus: Slower but deepest analysis

Reasoning Quality Rankings

1. Opus: Superior for complex multi-step problems
2. Sonnet 4: Excellent for most development scenarios
3. Sonnet 3.5: Good reasoning with some limitations
4. Haiku: Basic reasoning only

Cost Efficiency Rankings

1. Haiku: Cheapest per task (limited capability)
2. Sonnet 3.5: Good value for basic development
3. Sonnet 4: Best performance per dollar
4. Opus: Premium pricing for premium capability

Common Model Selection Mistakes

Mistake 1: Using Opus for everything

• Problem: 5x higher costs with slower responses
• Solution: Default to Sonnet 4, escalate selectively

Mistake 2: Staying on Haiku too long

• Problem: Poor code quality, missed issues
• Solution: Upgrade to Sonnet for any real development

Mistake 3: Not switching models mid-session

• Problem: Using wrong model for current task
• Solution: Learn to switch with /model command

Quick Reference

For beginners: Start with Sonnet 3.5 to learn workflows, upgrade to Sonnet 4 when comfortable.

For daily development: Sonnet 4 as default with Opus for complex debugging.

For budget optimization: Strategic switching based on task complexity.

For learning: Check our configuration guide to set up model defaults.

Master model selection and you'll code faster while spending less. Most tasks need Sonnet's balanced power, not Opus's premium capabilities.

Next Action: Set up your optimal model configuration with our performance optimization guide, then learn advanced context management techniques.