Gemini 3 Pro Reasoning vs o4 Reasoning: which model should you choose?
We compared Gemini 3 Pro Reasoning and o4 Reasoning on price, context window and 12 benchmarks. Gemini 3 Pro Reasoning and o4 Reasoning are effectively tied on the index average; Gemini 3 Pro Reasoning is cheaper on a blended 3:1 basis.
Gemini 3 Pro Reasoning
Gemini 3 Pro Reasoning is a frontier model from Google DeepMind. It offers a 200,000-token context window, costs $19.69 per million input tokens and $98.36 per million output tokens, and averages 87.5 across the index's benchmark suite.
- Input
- $19.69 / 1M
- Output
- $98.36 / 1M
- Context
- 200,000
- Avg score
- 87.5
- Open weights
- No
o4 Reasoning
o4 Reasoning is a frontier model from OpenAI. It offers a 1,000,000-token context window, costs $19.69 per million input tokens and $103.53 per million output tokens, and averages 87.5 across the index's benchmark suite.
- Input
- $19.69 / 1M
- Output
- $103.53 / 1M
- Context
- 1,000,000
- Avg score
- 87.5
- Open weights
- No
Specification comparison
| Spec | Gemini 3 Pro Reasoning | o4 Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $19.69 | $19.69 | Tie |
| Output price / 1M | $98.36 | $103.53 | A |
| Context window | 200,000 | 1,000,000 | B |
| Max output | 8,192 | 128,000 | B |
| Average score | 87.5 | 87.5 | Tie |
| Arena Elo | 1485.0 | 1472.2 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Gemini 3 Pro Reasoning wins 4, o4 Reasoning wins 7, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Gemini 3 Pro Reasoning | o4 Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 90.1 | 86.1 | 4.0 | Gemini 3 Pro Reasoning |
| GPQA Diamond | 83.9 | 84.0 | 0.1 | o4 Reasoning |
| SWE-bench Verified | 76.3 | 76.4 | 0.1 | o4 Reasoning |
| HumanEval | 90.2 | 90.2 | 0.0 | Tie |
| MATH-500 | 93.3 | 94.8 | 1.5 | o4 Reasoning |
| AIME 2025 | 88.8 | 90.3 | 1.5 | o4 Reasoning |
| LiveCodeBench | 82.0 | 83.4 | 1.4 | o4 Reasoning |
| IFEval | 93.8 | 94.5 | 0.7 | o4 Reasoning |
| TruthfulQA | 90.3 | 89.0 | 1.3 | Gemini 3 Pro Reasoning |
| HellaSwag | 93.5 | 92.4 | 1.1 | Gemini 3 Pro Reasoning |
| MMMU | 80.8 | 81.8 | 1.0 | o4 Reasoning |
| Arena Elo | 1485.0 | 1472.2 | 12.8 | Gemini 3 Pro Reasoning |
Price analysis
On a blended 3:1 input-to-output basis, Gemini 3 Pro Reasoning costs about $39.36 per million tokens and o4 Reasoning costs about $40.65. Gemini 3 Pro Reasoning is roughly 3% cheaper than o4 Reasoning. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
o4 Reasoning has the larger context window at 1,000,000 tokens, compared with 200,000 for Gemini 3 Pro Reasoning. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Gemini 3 Pro Reasoning wins 4, o4 Reasoning wins 7, and 1 are tied. The two models are effectively tied on the index average at 87.5.
The price picture favours Gemini 3 Pro Reasoning. The context picture favours o4 Reasoning. Those two dimensions often matter more than a few benchmark points once a model is good enough for the task.
If you need a single default, start with Gemini 3 Pro Reasoning if cost is the constraint and o4 Reasoning if context is the constraint. Test both on a sample of your own traffic before committing.
Choose Gemini 3 Pro Reasoning if
- Unit cost matters and you want the cheaper blended price.
Choose o4 Reasoning if
- You need the larger 1,000,000-token context window.
- You need the larger 128,000-token output limit.
FAQ
Is Gemini 3 Pro Reasoning better than o4 Reasoning?
The two models are effectively tied on the index average at 87.5. The better choice depends on price, context and your task. Gemini 3 Pro Reasoning wins 4 benchmarks, o4 Reasoning wins 7.
Which is cheaper, Gemini 3 Pro Reasoning or o4 Reasoning?
Gemini 3 Pro Reasoning is cheaper on a blended 3:1 basis at about $39.36 per million tokens, versus $40.65 for o4 Reasoning.
Which has the larger context window?
o4 Reasoning has the larger context window at 1,000,000 tokens. Gemini 3 Pro Reasoning has 200,000 tokens.
Are these models open weights?
Gemini 3 Pro Reasoning is proprietary; o4 Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with Gemini 3 Pro Reasoning if cost is the constraint and o4 Reasoning if context is the constraint. Test both on a sample of your own traffic before committing.