Grok 4 vs o3 Pro: which model should you choose?
We compared Grok 4 and o3 Pro on price, context window and 12 benchmarks. Grok 4 has the stronger average benchmark score; o3 Pro is cheaper on a blended 3:1 basis.
Grok 4
Grok 4 is a frontier model from xAI. It offers a 200,000-token context window, costs $17.90 per million input tokens and $84.75 per million output tokens, and averages 86.5 across the index's benchmark suite.
- Input
- $17.90 / 1M
- Output
- $84.75 / 1M
- Context
- 200,000
- Avg score
- 86.5
- Open weights
- No
o3 Pro
o3 Pro is a frontier model from OpenAI. It offers a 400,000-token context window, costs $17.89 per million input tokens and $81.48 per million output tokens, and averages 85.8 across the index's benchmark suite.
- Input
- $17.89 / 1M
- Output
- $81.48 / 1M
- Context
- 400,000
- Avg score
- 85.8
- Open weights
- No
Specification comparison
| Spec | Grok 4 | o3 Pro | Edge |
|---|---|---|---|
| Input price / 1M | $17.90 | $17.89 | B |
| Output price / 1M | $84.75 | $81.48 | B |
| Context window | 200,000 | 400,000 | B |
| Max output | 32,768 | 8,192 | A |
| Average score | 86.5 | 85.8 | A |
| Arena Elo | 1457.8 | 1471.9 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Grok 4 wins 6, o3 Pro wins 6, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Grok 4 | o3 Pro | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 87.8 | 84.3 | 3.5 | Grok 4 |
| GPQA Diamond | 82.6 | 78.7 | 3.9 | Grok 4 |
| SWE-bench Verified | 77.9 | 76.9 | 1.0 | Grok 4 |
| HumanEval | 92.0 | 90.6 | 1.4 | Grok 4 |
| MATH-500 | 90.8 | 92.4 | 1.6 | o3 Pro |
| AIME 2025 | 82.2 | 83.5 | 1.3 | o3 Pro |
| LiveCodeBench | 82.2 | 82.4 | 0.2 | o3 Pro |
| IFEval | 91.6 | 90.9 | 0.7 | Grok 4 |
| TruthfulQA | 87.6 | 88.4 | 0.8 | o3 Pro |
| HellaSwag | 93.9 | 92.5 | 1.4 | Grok 4 |
| MMMU | 82.9 | 83.1 | 0.2 | o3 Pro |
| Arena Elo | 1457.8 | 1471.9 | 14.1 | o3 Pro |
Price analysis
On a blended 3:1 input-to-output basis, Grok 4 costs about $34.61 per million tokens and o3 Pro costs about $33.79. o3 Pro is roughly 2% cheaper than Grok 4. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
o3 Pro has the larger context window at 400,000 tokens, compared with 200,000 for Grok 4. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Grok 4 wins 6, o3 Pro wins 6, and 0 are tied. On the index average, Grok 4 leads o3 Pro by 0.7 points (86.5 versus 85.8).
The price picture favours o3 Pro. The context picture favours o3 Pro. 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 Grok 4 for quality-sensitive work and o3 Pro for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose Grok 4 if
- You want the higher average benchmark score in this index.
- You need the larger 32,768-token output limit.
Choose o3 Pro if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 400,000-token context window.
FAQ
Is Grok 4 better than o3 Pro?
On the index average, Grok 4 leads o3 Pro by 0.7 points (86.5 versus 85.8). The better choice depends on price, context and your task. Grok 4 wins 6 benchmarks, o3 Pro wins 6.
Which is cheaper, Grok 4 or o3 Pro?
o3 Pro is cheaper on a blended 3:1 basis at about $33.79 per million tokens, versus $34.61 for Grok 4.
Which has the larger context window?
o3 Pro has the larger context window at 400,000 tokens. Grok 4 has 200,000 tokens.
Are these models open weights?
Grok 4 is proprietary; o3 Pro is proprietary.
Which should I choose for production?
If you need a single default, start with Grok 4 for quality-sensitive work and o3 Pro for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.