Gemini 2.5 Flash-Lite Preview (Sep '25) (Reasoning) vs GPT-5.1 (high)
Comparing 2 AI models · 5 benchmarks · Google, OpenAI
Composite Indices
Intelligence, Coding, Math
Standard Benchmarks
Academic and industry benchmarks
Benchmark Winners
Gemini 2.5 Flash-Lite Preview (Sep '25) (Reasoning)
No clear wins
GPT-5.1 (high)
- GPQA
- MMLU Pro
- HLE
- LiveCodeBench
- AIME 2025
| Metric | Go Gemini 2.5 Flash-Lite Preview (Sep '25) (Reasoning) | Op GPT-5.1 (high) |
|---|---|---|
| Pricing Per 1M tokens | ||
| Input Cost | $0.10/1M | $1.25/1M |
| Output Cost | $0.40/1M | $10.00/1M |
| Blended Cost 3:1 input/output ratio | $0.18/1M | $3.44/1M |
| Specifications | ||
| Organization Model creator | OpenAI | |
| Release Date Launch date | Sep 8, 2025 | Nov 13, 2025 |
| Performance & Speed | ||
| Throughput Output speed | 5.3 tok/s | 273.7 tok/s |
| Time to First Token (TTFT) Initial response delay | 3556ms | 8572ms |
| Latency Time to first answer token | 3556ms | 8572ms |
| Composite Indices | ||
| Intelligence Index Overall reasoning capability | 47.9 | 69.7 |
| Coding Index Programming ability | 36.5 | 57.5 |
| Math Index Mathematical reasoning | 68.7 | 94.0 |
| Standard Benchmarks | ||
| GPQA Graduate-level reasoning | 70.9% | 87.3% |
| MMLU Pro Advanced knowledge | 80.8% | 87.0% |
| HLE Hard language evaluation | 6.6% | 26.5% |
| LiveCodeBench Real-world coding tasks | 68.8% | 86.8% |
| MATH 500 Mathematical problems | — | — |
| AIME 2025 Advanced math competition | 68.7% | 94.0% |
| AIME (Original) Math olympiad problems | — | — |
| SciCode Scientific code generation | 28.7% | 43.3% |
| LCR Code review capability | 59.0% | 75.0% |
| IFBench Instruction-following | 52.6% | 72.9% |
| TAU-bench v2 Tool use & agentic tasks | 30.7% | 81.9% |
| TerminalBench Hard CLI command generation | 12.1% | 42.6% |
Key Takeaways
Gemini 2.5 Flash-Lite Preview (Sep '25) (Reasoning) offers the best value at $0.10/1M, making it ideal for high-volume applications and cost-conscious projects.
GPT-5.1 (high) leads in reasoning capabilities with a 87.3% GPQA score, excelling at complex analytical tasks and problem-solving.
GPT-5.1 (high) achieves a 57.5 coding index, making it the top choice for software development and code generation tasks.
All models support context windows of ∞+ tokens, suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
Gemini 2.5 Flash-Lite Preview (Sep '25) (Reasoning)
- Cost-sensitive applications
- High-volume processing
GPT-5.1 (high)
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
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Gemini 2.5 Flash-Lite Preview (Sep '25) (Reasoning) GPT-5.1 (high)