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o3 vs Gemini 2.5 Flash
A detailed comparison of o3 (OpenAI) and Gemini 2.5 Flash (Google) across pricing, performance, and features.
Pricing Comparison
| Metric | o3 | Gemini 2.5 Flash | Difference |
|---|---|---|---|
| Input / 1M tokens | $0.40 | $0.15 | -63% |
| Output / 1M tokens | $1.60 | $0.60 | -63% |
| Context window | 200K | 1M | — |
| Max output | 100K | 65.536K | — |
Benchmark Comparison
| Benchmark | o3 | Gemini 2.5 Flash |
|---|---|---|
| MMLU-Pro | 87% | 76% |
| HumanEval | 94.5% | 89.5% |
| GPQA | 79.2% | — |
Capabilities
| Capability | o3 | Gemini 2.5 Flash |
|---|---|---|
| code | ✓ | ✓ |
| reasoning | ✓ | ✓ |
| text | ✓ | ✓ |
| tool-use | ✓ | ✓ |
| vision | ✓ | ✓ |
o3 Strengths
- ✓Recently repriced — now very cheap
- ✓Excellent logical reasoning
- ✓200K context window
o3 Weaknesses
- ✗Slower due to reasoning overhead
- ✗Overkill for simple tasks
Gemini 2.5 Flash Strengths
- ✓One of the cheapest models available
- ✓1M context at budget pricing
- ✓Free tier available
Gemini 2.5 Flash Weaknesses
- ✗Weaker than Flash 3 on most benchmarks
- ✗Output quality inconsistent on edge cases
Quick Verdict
Best value: Gemini 2.5 Flash is the more affordable option at $0.15/$0.6 per 1M tokens.
Higher benchmarks: o3 scores higher on average across available benchmarks (86.9% avg).
Larger context: Gemini 2.5 Flash supports 1M tokens.
Choose Gemini 2.5 Flash if cost matters most. Choose o3 if you need the best possible quality for complex tasks.