Grok 4 vs o4: which model should you choose?
We compared Grok 4 and o4 on price, context window and 12 benchmarks. Grok 4 has the stronger average benchmark score; o4 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
o4
o4 is a frontier model from OpenAI. It offers a 2,000,000-token context window, costs $17.74 per million input tokens and $66.00 per million output tokens, and averages 85.4 across the index's benchmark suite.
- Input
- $17.74 / 1M
- Output
- $66.00 / 1M
- Context
- 2,000,000
- Avg score
- 85.4
- Open weights
- No
Specification comparison
| Spec | Grok 4 | o4 | Edge |
|---|---|---|---|
| Input price / 1M | $17.90 | $17.74 | B |
| Output price / 1M | $84.75 | $66.00 | B |
| Context window | 200,000 | 2,000,000 | B |
| Max output | 32,768 | 8,192 | A |
| Average score | 86.5 | 85.4 | A |
| Arena Elo | 1457.8 | 1469.4 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Grok 4 wins 9, o4 wins 3, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Grok 4 | o4 | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 87.8 | 85.3 | 2.5 | Grok 4 |
| GPQA Diamond | 82.6 | 82.3 | 0.3 | Grok 4 |
| SWE-bench Verified | 77.9 | 74.8 | 3.1 | Grok 4 |
| HumanEval | 92.0 | 89.6 | 2.4 | Grok 4 |
| MATH-500 | 90.8 | 90.5 | 0.3 | Grok 4 |
| AIME 2025 | 82.2 | 85.3 | 3.1 | o4 |
| LiveCodeBench | 82.2 | 81.4 | 0.8 | Grok 4 |
| IFEval | 91.6 | 92.8 | 1.2 | o4 |
| TruthfulQA | 87.6 | 85.0 | 2.6 | Grok 4 |
| HellaSwag | 93.9 | 91.0 | 2.9 | Grok 4 |
| MMMU | 82.9 | 80.9 | 2.0 | Grok 4 |
| Arena Elo | 1457.8 | 1469.4 | 11.6 | o4 |
Price analysis
On a blended 3:1 input-to-output basis, Grok 4 costs about $34.61 per million tokens and o4 costs about $29.80. o4 is roughly 14% cheaper than Grok 4. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
o4 has the larger context window at 2,000,000 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 9, o4 wins 3, and 0 are tied. On the index average, Grok 4 leads o4 by 1.1 points (86.5 versus 85.4).
The price picture favours o4. The context picture favours o4. 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 o4 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 o4 if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 2,000,000-token context window.
FAQ
Is Grok 4 better than o4?
On the index average, Grok 4 leads o4 by 1.1 points (86.5 versus 85.4). The better choice depends on price, context and your task. Grok 4 wins 9 benchmarks, o4 wins 3.
Which is cheaper, Grok 4 or o4?
o4 is cheaper on a blended 3:1 basis at about $29.80 per million tokens, versus $34.61 for Grok 4.
Which has the larger context window?
o4 has the larger context window at 2,000,000 tokens. Grok 4 has 200,000 tokens.
Are these models open weights?
Grok 4 is proprietary; o4 is proprietary.
Which should I choose for production?
If you need a single default, start with Grok 4 for quality-sensitive work and o4 for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.