Model comparison
Claude Sonnet 4 vs Grok 4 Fast
Claude Sonnet 4 is the stronger model overall, scoring 40.8 to 39.4 on the Noometry Index.
Last verified . 27 shared benchmarks.
Summary
- They share 27 benchmarks with published results for both. Claude Sonnet 4 scores higher in 5 categories and Grok 4 Fast in 4 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 33.7.
- The biggest single-benchmark swing is Fiction.LiveBench: 46.9% for Claude Sonnet 4 and 94.4% for Grok 4 Fast.
Side by side
| Claude Sonnet 4 | Grok 4 Fast | |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 40.8 | 39.4 |
| Released | 2025-05-22 | 2025-09-19 |
| Weights | Proprietary | Proprietary |
| Context window | 200K | — |
| Max output | 64K | — |
| Input $ / M tokens | $3 | — |
| Output $ / M tokens | $15 | — |
| Results tracked | 58 | 30 |
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Category by category
Coding Claude Sonnet 4 leads
Claude Sonnet 4: 43.5 (#88), Grok 4 Fast: 32.5 (#271)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| WeirdML | 46.1% | 42.9% |
| LMArena Coding | 1414 | 1429 |
| SWE-bench Verified (bash only) | 64.9% | — |
| Aider Polyglot | 61.3% | — |
| LMArena WebDev | — | 1159 |
| SciCode | 40% | — |
| GSO | 4.9% | — |
| ALE-Bench | 655.35 | — |
Agentic & Tool Use Claude Sonnet 4 leads
Claude Sonnet 4: 38.5 (#31), Grok 4 Fast: 29.5 (#86)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| Cybench | 35% | 30% |
| TheAgentCompany | 33.1% | — |
| τ²-bench Banking | — | 15.7% |
| DeepResearch Bench | 46.6% | — |
| OSWorld | 43.9% | — |
| LMArena Search | — | 1171 |
| METR Time Horizons | 62% | — |
Reasoning Too close to call
Claude Sonnet 4: 22.9 (#187), Grok 4 Fast: 22.2 (#201)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 5.9% | 5.3% |
| Kagi LLM Benchmark | 73% | 66.1% |
| ARC-AGI-1 | 40% | 48.5% |
| LMArena Hard Prompts | 1372 | 1412 |
| DTBench | 77.1% | 82.7% |
| Epoch Capabilities Index | 141.69 | 144.2 |
| ForecastBench | 60.2 | 60.5 |
| SimpleBench | 45.5% | — |
| CritPt | 0.3% | — |
| EnigmaEval | 3.1% | — |
| LMCA | 29% | — |
Math Claude Sonnet 4 leads
Claude Sonnet 4: 43.3 (#80), Grok 4 Fast: 38.9 (#123)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1375 | 1419 |
| OTIS Mock AIME 2024-2025 | 71.1% | — |
| Omni-MATH | 60.2% | — |
| MATH Level 5 | 84.4% | — |
| FrontierMath (Feb 2025 set) | 4.1% | — |
| FrontierMath Tier 4 (v1) | 0% | — |
Knowledge Claude Sonnet 4 leads
Claude Sonnet 4: 41.8 (#108), Grok 4 Fast: 32.0 (#214)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| Vectara Hallucination Rate | 10.3% | 19.7% |
| LMArena Expert | 1372 | 1411 |
| GPQA Diamond | 79.2% | — |
| Humanity's Last Exam | 7.8% | — |
| MMLU-Pro | 84.3% | — |
| Confabulations | 13.2% | — |
| GPQA (HELM) | 70.6% | — |
Multimodal Not comparable
Claude Sonnet 4: 26.2 (#121), Grok 4 Fast: —
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| LMArena Vision | 1191 | — |
| GeoBench | 37% | — |
| VPCT | 34% | — |
| MindCube | 44.8% | — |
Multilingual Grok 4 Fast leads
Claude Sonnet 4: 46.7 (#156), Grok 4 Fast: 51.3 (#111)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1333 | 1396 |
| LMArena Chinese | 1350 | 1457 |
| LMArena French | 1363 | 1431 |
| LMArena German | 1331 | 1383 |
| LMArena Japanese | 1302 | 1352 |
| LMArena Korean | 1291 | 1357 |
| LMArena Russian | 1355 | 1389 |
| LMArena Spanish | 1357 | 1415 |
Instruction Following Grok 4 Fast leads
Claude Sonnet 4: 71.7 (#145), Grok 4 Fast: 73.2 (#121)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1376 | 1387 |
| IFEval | 84% | — |
Long Context Grok 4 Fast leads
Claude Sonnet 4: 33.7 (#259), Grok 4 Fast: 63.2 (#3)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| Fiction.LiveBench | 46.9% | 94.4% |
| LMArena Longer Query | 1398 | 1415 |
Writing & Preference Grok 4 Fast leads
Claude Sonnet 4: 57.1 (#132), Grok 4 Fast: 60.0 (#102)
| Benchmark | Claude Sonnet 4 | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1351 | 1407 |
| LMArena Creative Writing | 1345 | 1387 |
| LMArena Multi-Turn | 1376 | 1414 |
| Short-Story Creative Writing | 81.4% | — |
| EQ-Bench Creative Writing | 1483 | — |
| WildBench | 83.8% | — |
Frequently asked questions
Is Claude Sonnet 4 better than Grok 4 Fast?
Claude Sonnet 4 is the stronger model overall, scoring 40.8 to 39.4 on the Noometry Index.
Is Claude Sonnet 4 or Grok 4 Fast better for coding?
Claude Sonnet 4 scores higher on coding benchmarks: 43.5 versus 32.5 in the Noometry coding category.
How many benchmarks do Claude Sonnet 4 and Grok 4 Fast share?
27 benchmarks have published results for both models. Claude Sonnet 4 has 58 scored results on Noometry and Grok 4 Fast has 30.