OpenAI o3 vs Mistral Small 3
Performance benchmarks + pricing comparison — updated April 2026
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 |
Mistral Small 3
MistralMistral's cost-effective model. Very affordable for general-purpose tasks.
| Input | $0.100/M |
| Output | $0.300/M |
| Context | 32K tokens |
| Best For | High-volume tasks, cost optimization |
| Benchmark | 42/100 |
Benchmark Performance Comparison
Third-party benchmark scores — higher is better. Data sourced from SWE-bench, LiveCodeBench, HumanEval, and BigCodeBench.
| Benchmark | OpenAI o3 | Mistral Small 3 | Leader |
|---|---|---|---|
| Overall Score | 85 | 42 | o3 leads by 43pts |
| SWE-bench Verified | 82 | 35 | o3 leads by 47pts |
| LiveCodeBench | 88 | 44 | o3 leads by 44pts |
| HumanEval | 96 | 65 | o3 leads by 31pts |
| BigCodeBench | 74 | 28 | o3 leads by 46pts |
Cost Comparison by Scenario
Estimated cost per project with 30% cache hit rate. Actual costs may vary based on usage patterns.
| Scenario | OpenAI o3 | Mistral Small 3 | Savings |
|---|---|---|---|
| Small Script (1K lines) | $1.55 | $0.01 | Mistral Small 3 saves $1.54 (99%) |
| Medium Feature (10K lines) | $11.50 | $0.10 | Mistral Small 3 saves $11.40 (99%) |
| Large Project (50K lines) | $57.50 | $0.47 | Mistral Small 3 saves $57.02 (99%) |
| Code Review (5K lines) | $2.75 | $0.02 | Mistral Small 3 saves $2.73 (99%) |
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 |
|---|---|---|---|
| OpenAI o3 | 85 | $0.167/pt | Higher cost per point |
| Mistral Small 3 | 42 | $0.002/pt | Better value |
Mistral Small 3 delivers the best value at $0.002 per score point.
Strengths & Weaknesses
OpenAI o3
- + Latest reasoning model
- + Top-tier across all benchmarks
- - Very expensive
- - Slow
Mistral Small 3
- + Ultra-cheap
- - Very limited capabilities
Verdict
Mistral Small 3 is cheaper at $0.100/M, but OpenAI o3 scores higher on benchmarks (85 vs 42).
Choose Mistral Small 3 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 Sonnet
AnthropicPrevious generation Sonnet. Still excellent for coding tasks at the same price point.
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.