Model comparison
Claude Sonnet 4 vs Grok 4.1 Fast
Claude Sonnet 4 and Grok 4.1 Fast score almost the same on the Noometry Index (40.6 vs 40.9), so choose on price, context window or the category you care about most.
Last verified . 24 shared benchmarks.
Summary
- They share 24 benchmarks with published results for both. Claude Sonnet 4 scores higher in 4 categories and Grok 4.1 Fast in 6 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.1 Fast leads 42.3 to 23.0.
- The biggest single-benchmark swing is DTBench: 77.1% for Claude Sonnet 4 and 87.7% for Grok 4.1 Fast.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.
- Claude Sonnet 4 accepts more context: 200K tokens versus 128K.
Side by side
| Claude Sonnet 4 | Grok 4.1 Fast | |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 40.6 | 40.9 |
| Released | 2025-05-22 | 2025-06-27 |
| Weights | Proprietary | Proprietary |
| Context window | 200K | 128K |
| Max output | 64K | 30K |
| Input $ / M tokens | $3 | $0.20 |
| Output $ / M tokens | $15 | $0.50 |
| Results tracked | 58 | 32 |
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Category by category
Coding Claude Sonnet 4 leads
Claude Sonnet 4: 44.0 (#70), Grok 4.1 Fast: 33.8 (#236)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| LMArena Coding | 1414 | 1411 |
| ALE-Bench | 655.35 | 394.93 |
| SWE-bench Verified (bash only) | 64.9% | — |
| Aider Polyglot | 61.3% | — |
| LMArena WebDev | — | 1241 |
| SciCode | 40% | — |
| GSO | 4.9% | — |
| WeirdML | 46.1% | — |
Agentic & Tool Use Claude Sonnet 4 leads
Claude Sonnet 4: 38.3 (#29), Grok 4.1 Fast: 36.1 (#35)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 69.6% |
| TheAgentCompany | 33.1% | — |
| τ²-bench Banking | — | 13.1% |
| Cybench | 35% | — |
| DeepResearch Bench | 46.6% | — |
| OSWorld | 43.9% | — |
| LMArena Search | — | 1171 |
| METR Time Horizons | 62% | — |
| Vending-Bench 2 | — | 1,107 |
Reasoning Grok 4.1 Fast leads
Claude Sonnet 4: 23.0 (#169), Grok 4.1 Fast: 42.3 (#45)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| SimpleBench | 45.5% | 56% |
| LMArena Hard Prompts | 1372 | 1407 |
| DTBench | 77.1% | 87.7% |
| ForecastBench | 60.2 | 61 |
| ARC-AGI-2 | 5.9% | — |
| Kagi LLM Benchmark | 73% | — |
| NYT Connections (extended) | — | 87.4% |
| ARC-AGI-1 | 40% | — |
| CritPt | 0.3% | — |
| EnigmaEval | 3.1% | — |
| LMCA | 29% | — |
| Epoch Capabilities Index | 141.69 | — |
Math Claude Sonnet 4 leads
Claude Sonnet 4: 41.5 (#71), Grok 4.1 Fast: 30.9 (#201)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| LMArena Math | 1375 | 1408 |
| MathArena Final-Answer Competitions | — | 60.9% |
| OTIS Mock AIME 2024-2025 | 71.1% | — |
| ProofBench | — | 4% |
| 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: 41.6 (#99), Grok 4.1 Fast: 32.6 (#203)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| Vectara Hallucination Rate | 10.3% | 17.8% |
| LMArena Expert | 1371 | 1398 |
| GPQA Diamond | 79.2% | — |
| Humanity's Last Exam | 7.8% | — |
| MMLU-Pro | 84.3% | — |
| Confabulations | 13.2% | — |
| GPQA (HELM) | 70.6% | — |
Multimodal Grok 4.1 Fast leads
Claude Sonnet 4: 25.6 (#116), Grok 4.1 Fast: 36.3 (#71)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| LMArena Vision | 1191 | 1201 |
| GeoBench | 37% | — |
| VPCT | 34% | — |
| MindCube | 44.8% | — |
Multilingual Grok 4.1 Fast leads
Claude Sonnet 4: 46.9 (#151), Grok 4.1 Fast: 51.1 (#110)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| LMArena Non-English | 1333 | 1391 |
| LMArena Chinese | 1351 | 1441 |
| LMArena French | 1364 | 1416 |
| LMArena German | 1331 | 1404 |
| LMArena Japanese | 1301 | 1347 |
| LMArena Korean | 1293 | 1361 |
| LMArena Russian | 1355 | 1387 |
| LMArena Spanish | 1356 | 1411 |
Instruction Following Too close to call
Claude Sonnet 4: 71.8 (#141), Grok 4.1 Fast: 72.8 (#127)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| LMArena Instruction Following | 1375 | 1376 |
| IFEval | 84% | — |
Long Context Grok 4.1 Fast leads
Claude Sonnet 4: 33.6 (#254), Grok 4.1 Fast: 42.4 (#121)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| LMArena Longer Query | 1398 | 1390 |
| Fiction.LiveBench | 46.9% | — |
Writing & Preference Too close to call
Claude Sonnet 4: 57.3 (#127), Grok 4.1 Fast: 57.4 (#126)
| Benchmark | Claude Sonnet 4 | Grok 4.1 Fast |
|---|---|---|
| LMArena Text | 1351 | 1408 |
| LMArena Creative Writing | 1345 | 1394 |
| EQ-Bench Creative Writing | 1483 | 1327 |
| LMArena Multi-Turn | 1376 | 1389 |
| Short-Story Creative Writing | 81.4% | — |
| WildBench | 83.8% | — |
Frequently asked questions
Is Claude Sonnet 4 better than Grok 4.1 Fast?
Claude Sonnet 4 and Grok 4.1 Fast score almost the same on the Noometry Index (40.6 vs 40.9), so choose on price, context window or the category you care about most.
Which is cheaper, Claude Sonnet 4 or Grok 4.1 Fast?
Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Claude Sonnet 4 lists at $3 and $15.
Is Claude Sonnet 4 or Grok 4.1 Fast better for coding?
Claude Sonnet 4 scores higher on coding benchmarks: 44.0 versus 33.8 in the Noometry coding category.
Which has the bigger context window?
Claude Sonnet 4 does, with 200K tokens against 128K.
How many benchmarks do Claude Sonnet 4 and Grok 4.1 Fast share?
24 benchmarks have published results for both models. Claude Sonnet 4 has 58 scored results on Noometry and Grok 4.1 Fast has 32.