Claude 3.5 Sonnet vs OpenAI o3
Performance benchmarks + pricing comparison — updated April 2026
Claude 3.5 Sonnet
AnthropicPrevious generation Sonnet. Still excellent for coding tasks at the same price point.
| Input | $3.00/M |
| Output | $15.00/M |
| Context | 200K tokens |
| Best For | Coding assistants, web development, data analysis |
| Benchmark | 72/100 |
OpenAI o3
OpenAINext generation reasoning model. Improved coding and math over o1.
| Input | $10.00/M |
| Output | $40.00/M |
| Context | 200K tokens |
| Best For | Advanced coding, complex problem-solving |
| Benchmark | 85/100 |
Benchmark Performance Comparison
Third-party benchmark scores — higher is better. Data sourced from SWE-bench, LiveCodeBench, HumanEval, and BigCodeBench.
| Benchmark | Claude 3.5 Sonnet | OpenAI o3 | Leader |
|---|---|---|---|
| Overall Score | 72 | 85 | o3 leads by 13pts |
| SWE-bench Verified | 68 | 82 | o3 leads by 14pts |
| LiveCodeBench | 75 | 88 | o3 leads by 13pts |
| HumanEval | 90 | 96 | o3 leads by 6pts |
| BigCodeBench | 58 | 74 | o3 leads by 16pts |
Cost Comparison by Scenario
Estimated cost per project with 30% cache hit rate. Actual costs may vary based on usage patterns.
| Scenario | Claude 3.5 Sonnet | OpenAI o3 | Savings |
|---|---|---|---|
| Small Script (1K lines) | $0.62 | $1.55 | Claude 3.5 Sonnet saves $0.93 (60%) |
| Medium Feature (10K lines) | $4.66 | $11.50 | Claude 3.5 Sonnet saves $6.84 (60%) |
| Large Project (50K lines) | $23.29 | $57.50 | Claude 3.5 Sonnet saves $34.21 (60%) |
| Code Review (5K lines) | $1.20 | $2.75 | Claude 3.5 Sonnet saves $1.55 (56%) |
Value Analysis (Price per Benchmark Score Point)
Lower is better — how much you pay for each point of benchmark performance.
| Model | Overall Score | Price per Score Point | Verdict |
|---|---|---|---|
| Claude 3.5 Sonnet | 72 | $0.042/pt | Better value |
| OpenAI o3 | 85 | $0.167/pt | Higher cost per point |
Claude 3.5 Sonnet delivers the best value at $0.042 per score point.
Strengths & Weaknesses
Claude 3.5 Sonnet
- + Balanced performance
- + Computer use capability
- + Artifact generation
- - Older architecture
- - Falling behind Sonnet 4
OpenAI o3
- + Latest reasoning model
- + Top-tier across all benchmarks
- - Very expensive
- - Slow
Verdict
Claude 3.5 Sonnet is cheaper at $3.00/M, but OpenAI o3 scores higher on benchmarks (85 vs 72).
Choose Claude 3.5 Sonnet for cost-sensitive projects, OpenAI o3 when performance matters most.
Compare with Other Models
Claude Sonnet 4
AnthropicAnthropic's balanced model for coding and general tasks. Best price-performance ratio in the Claude family.
Claude Opus 4
AnthropicAnthropic's most powerful model. Best for complex reasoning and challenging coding tasks.
Claude 3.5 Haiku
AnthropicFast, cost-effective model for high-volume tasks. Great for code review and simple queries.
Claude 3 Opus
AnthropicFirst generation Opus. Highest reasoning capability in the Claude 3 family.
Claude 3 Sonnet
AnthropicFirst generation Sonnet. Balanced performance for general tasks.
Claude 3 Haiku
AnthropicCheapest Claude model. Fast responses for simple tasks and basic coding.