Model comparison
Grok 4.1 Fast vs o3-pro
o3-pro is the stronger model overall, scoring 42.9 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 127× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. Grok 4.1 Fast scores higher in 3 categories and o3-pro in 2 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in long context, where o3-pro leads 72.2 to 42.4.
- The biggest single-benchmark swing is Vectara Hallucination Rate: 17.8% for Grok 4.1 Fast and 23.3% for o3-pro.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $20 / $80 for o3-pro.
- o3-pro accepts more context: 200K tokens versus 128K.
Side by side
| Grok 4.1 Fast | o3-pro | |
|---|---|---|
| Provider | xAI | OpenAI |
| Noometry Index | 41.4 | 42.9 |
| Released | 2025-06-27 | 2025-06-10 |
| Weights | Proprietary | Proprietary |
| Context window | 128K | 200K |
| Max output | 30K | 100K |
| Input $ / M tokens | $0.20 | $20 |
| Output $ / M tokens | $0.50 | $80 |
| Results tracked | 32 | 12 |
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Category by category
Coding o3-pro leads
Grok 4.1 Fast: 34.1 (#245), o3-pro: 55.5 (#24)
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| Aider Polyglot | — | 84.9% |
| LMArena WebDev | 1242 | — |
| WeirdML | — | 58.2% |
| LMArena Coding | 1411 | — |
| ALE-Bench | 394.93 | — |
Agentic & Tool Use Not comparable
Grok 4.1 Fast: 36.3 (#39), o3-pro: —
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| Berkeley Function Calling Leaderboard | 69.6% | — |
| τ²-bench Banking | 13.1% | — |
| LMArena Search | 1171 | — |
| Vending-Bench 2 | 1,107 | — |
Reasoning Grok 4.1 Fast leads
Grok 4.1 Fast: 43.4 (#49), o3-pro: 23.8 (#171)
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| DTBench | 87.7% | 86.9% |
| ARC-AGI-2 | — | 4.9% |
| SimpleBench | 56% | — |
| Kagi LLM Benchmark | — | 72.1% |
| NYT Connections (extended) | 87.4% | — |
| ARC-AGI-1 | — | 59.3% |
| LMArena Hard Prompts | 1407 | — |
| LMCA | — | 38.5% |
| Epoch Capabilities Index | — | 147.42 |
| ForecastBench | 61 | — |
Math Not comparable
Grok 4.1 Fast: 31.9 (#221), o3-pro: —
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| MathArena Final-Answer Competitions | 60.9% | — |
| ProofBench | 4% | — |
| LMArena Math | 1408 | — |
Knowledge Grok 4.1 Fast leads
Grok 4.1 Fast: 33.1 (#207), o3-pro: 29.5 (#238)
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| Vectara Hallucination Rate | 17.8% | 23.3% |
| Confabulations | — | 14.2% |
| LMArena Expert | 1399 | — |
Multimodal Not comparable
Grok 4.1 Fast: 37.0 (#76), o3-pro: —
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| LMArena Vision | 1201 | — |
Multilingual Not comparable
Grok 4.1 Fast: 51.0 (#114), o3-pro: —
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| LMArena Non-English | 1391 | — |
| LMArena Chinese | 1441 | — |
| LMArena French | 1415 | — |
| LMArena German | 1404 | — |
| LMArena Japanese | 1349 | — |
| LMArena Korean | 1361 | — |
| LMArena Russian | 1387 | — |
| LMArena Spanish | 1413 | — |
Instruction Following Not comparable
Grok 4.1 Fast: 72.7 (#133), o3-pro: —
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| LMArena Instruction Following | 1376 | — |
Long Context o3-pro leads
Grok 4.1 Fast: 42.4 (#126), o3-pro: 72.2 (#1)
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
| LMArena Longer Query | 1390 | — |
Writing & Preference Too close to call
Grok 4.1 Fast: 57.2 (#131), o3-pro: 57.1 (#133)
| Benchmark | Grok 4.1 Fast | o3-pro |
|---|---|---|
| LMArena Text | 1408 | — |
| LMArena Creative Writing | 1394 | — |
| Short-Story Creative Writing | — | 84.4% |
| EQ-Bench Creative Writing | 1327 | — |
| LMArena Multi-Turn | 1389 | — |
Frequently asked questions
Is Grok 4.1 Fast better than o3-pro?
o3-pro is the stronger model overall, scoring 42.9 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 127× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Which is cheaper, Grok 4.1 Fast or o3-pro?
Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; o3-pro lists at $20 and $80.
Is Grok 4.1 Fast or o3-pro better for coding?
o3-pro scores higher on coding benchmarks: 55.5 versus 34.1 in the Noometry coding category.
Which has the bigger context window?
o3-pro does, with 200K tokens against 128K.
How many benchmarks do Grok 4.1 Fast and o3-pro share?
2 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and o3-pro has 12.