Model comparison
Claude Opus 5 vs Grok 4.1 Fast
Claude Opus 5 is the stronger model overall, scoring 67.8 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 36× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Last verified . 27 shared benchmarks.
Summary
- They share 27 benchmarks with published results for both. Claude Opus 5 scores higher in 10 categories and Grok 4.1 Fast in 0 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5 leads 86.2 to 31.9.
- The biggest single-benchmark swing is ProofBench: 99% for Claude Opus 5 and 4% for Grok 4.1 Fast.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $5 / $25 for Claude Opus 5.
- Claude Opus 5 accepts more context: 1M tokens versus 128K.
Side by side
| Claude Opus 5 | Grok 4.1 Fast | |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 67.8 | 41.4 |
| Released | 2026-07-24 | 2025-06-27 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 128K |
| Max output | 128K | 30K |
| Input $ / M tokens | $5 | $0.20 |
| Output $ / M tokens | $25 | $0.50 |
| Results tracked | 57 | 32 |
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Category by category
Coding Claude Opus 5 leads
Claude Opus 5: 67.5 (#5), Grok 4.1 Fast: 34.1 (#245)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| LMArena WebDev | 1691 | 1242 |
| LMArena Coding | 1534 | 1411 |
| ALE-Bench | 2,165 | 394.93 |
| DeepSWE | 73.6% | — |
| FrontierCode | 53.4% | — |
| CursorBench | 46.6% | — |
| FrontierSWE | 52% | — |
| SciCode | 56.4% | — |
| WeirdML | 91.8% | — |
Agentic & Tool Use Claude Opus 5 leads
Claude Opus 5: 55.6 (#1), Grok 4.1 Fast: 36.3 (#39)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| τ²-bench Banking | 48.7% | 13.1% |
| Vending-Bench 2 | 11,182 | 1,107 |
| APEX-Agents | 65.8% | — |
| Berkeley Function Calling Leaderboard | — | 69.6% |
| OSWorld 2.0 | 31.4% | — |
| PostTrainBench | 35% | — |
| BALROG | 63.4% | — |
| GBAEval | 79.6% | — |
| GDP.pdf | 24% | — |
| LMArena Search | — | 1171 |
Reasoning Claude Opus 5 leads
Claude Opus 5: 77.2 (#4), Grok 4.1 Fast: 43.4 (#49)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| SimpleBench | 80.6% | 56% |
| NYT Connections (extended) | 94.3% | 87.4% |
| LMArena Hard Prompts | 1526 | 1407 |
| DTBench | 97.9% | 87.7% |
| ARC-AGI-2 | 90.4% | — |
| ARC-AGI-1 | 97.5% | — |
| CritPt | 29.1% | — |
| Chess Puzzles | 42% | — |
| EBR-Bench | 45.7% | — |
| Mystery Game Puzzles | 59% | — |
| LMCA | 64.5% | — |
| Bench to the Future 3 | 0.12 | — |
| Epoch Capabilities Index | 162.78 | — |
| ForecastBench | — | 61 |
Math Claude Opus 5 leads
Claude Opus 5: 86.2 (#8), Grok 4.1 Fast: 31.9 (#221)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| ProofBench | 99% | 4% |
| LMArena Math | 1531 | 1408 |
| FrontierMath (Tiers 1-3) | 85.6% | — |
| FrontierMath Tier 4 | 73.2% | — |
| MathArena Final-Answer Competitions | — | 60.9% |
| OTIS Mock AIME 2024-2025 | 98.9% | — |
Knowledge Claude Opus 5 leads
Claude Opus 5: 66.8 (#9), Grok 4.1 Fast: 33.1 (#207)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Expert | 1557 | 1399 |
| GPQA Diamond | 93.9% | — |
| SimpleQA Verified | 59.9% | — |
| Vectara Hallucination Rate | — | 17.8% |
Multimodal Claude Opus 5 leads
Claude Opus 5: 50.8 (#8), Grok 4.1 Fast: 37.0 (#76)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Vision | 1319 | 1201 |
| Blueprint-Bench 2 | 30.4% | — |
| Furniture Assembly | 60.8% | — |
| LMArena Document | 1516 | — |
Multilingual Claude Opus 5 leads
Claude Opus 5: 58.8 (#4), Grok 4.1 Fast: 51.0 (#114)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Non-English | 1501 | 1391 |
| LMArena Chinese | 1574 | 1441 |
| LMArena French | 1519 | 1415 |
| LMArena German | 1524 | 1404 |
| LMArena Japanese | 1516 | 1349 |
| LMArena Korean | 1521 | 1361 |
| LMArena Russian | 1507 | 1387 |
| LMArena Spanish | 1519 | 1413 |
Instruction Following Claude Opus 5 leads
Claude Opus 5: 79.2 (#7), Grok 4.1 Fast: 72.7 (#133)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Instruction Following | 1517 | 1376 |
Long Context Claude Opus 5 leads
Claude Opus 5: 46.5 (#21), Grok 4.1 Fast: 42.4 (#126)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Longer Query | 1515 | 1390 |
Writing & Preference Claude Opus 5 leads
Claude Opus 5: 79.2 (#1), Grok 4.1 Fast: 57.2 (#131)
| Benchmark | Claude Opus 5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Text | 1507 | 1408 |
| LMArena Creative Writing | 1491 | 1394 |
| EQ-Bench Creative Writing | 2133 | 1327 |
| LMArena Multi-Turn | 1499 | 1389 |
| EQ-Bench 4 | 1385 | — |
Frequently asked questions
Is Claude Opus 5 better than Grok 4.1 Fast?
Claude Opus 5 is the stronger model overall, scoring 67.8 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 36× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 5 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 Opus 5 lists at $5 and $25.
Is Claude Opus 5 or Grok 4.1 Fast better for coding?
Claude Opus 5 scores higher on coding benchmarks: 67.5 versus 34.1 in the Noometry coding category.
Which has the bigger context window?
Claude Opus 5 does, with 1M tokens against 128K.
How many benchmarks do Claude Opus 5 and Grok 4.1 Fast share?
27 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and Grok 4.1 Fast has 32.