# Claude Opus 4.8 vs Grok 4.20 (Non-Reasoning)

> Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 48.5 on the Noometry Index. Grok 4.20 (Non-Reasoning) costs 6.4× less per token, which makes it the better buy when Claude Opus 4.8's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-opus-4-8-vs-grok-4-20
- Last updated: 2026-10-10
- Shared benchmarks: 42

## Summary

- They share 42 benchmarks with published results for both. Claude Opus 4.8 scores higher in 9 categories and Grok 4.20 (Non-Reasoning) in 1 category; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 4.8 leads 78.2 to 48.0.
- The biggest single-benchmark swing is ProofBench: 69% for Claude Opus 4.8 and 14% for Grok 4.20 (Non-Reasoning).
- Grok 4.20 (Non-Reasoning) is cheaper at $1.25 / $2.50 per million input/output tokens, against $5 / $25 for Claude Opus 4.8.

## Snapshot

| | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 60.7 | 48.5 |
| Rank | 9 | 48 |
| Context | 1M | 1M |
| Input $/M | $5 | $1.25 |
| Output $/M | $25 | $2.50 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Opus 4.8: 60.2 (#9)
- Grok 4.20 (Non-Reasoning): 41.8 (#104)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena WebDev | 1556 | 1374 |
| WeirdML | 82.9% | 52.3% |
| LMArena Coding | 1491 | 1458 |
| ALE-Bench | 1,564 | 1,150 |
| DeepSWE | 59% | — |
| FrontierCode | 46.5% | — |
| SciCode | 53.5% | — |
| GSO | 47.1% | — |

## Agentic & Tool Use

- Claude Opus 4.8: 47.6 (#10)
- Grok 4.20 (Non-Reasoning): 34.3 (#43)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| τ²-bench Banking | 39.7% | 18% |
| LMArena Search | 1204 | 1189 |
| Vending-Bench 2 | 5,787 | 4,663 |
| Terminal-Bench | — | 57.3% |
| APEX-Agents | 48.9% | — |
| OSWorld 2.0 | 20.6% | — |
| Remote Labor Index | 8.3% | — |
| DeepResearch Bench | 50.2% | — |
| PostTrainBench | 33.8% | — |
| GBAEval | 70.9% | — |
| GDP.pdf | 24% | — |

## Reasoning

- Claude Opus 4.8: 64.6 (#14)
- Grok 4.20 (Non-Reasoning): 52.2 (#30)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| ARC-AGI-2 | 72.1% | 65.1% |
| Kagi LLM Benchmark | 88.8% | 75% |
| NYT Connections (extended) | 91.1% | 85.4% |
| ARC-AGI-1 | 92.5% | 89.5% |
| Chess Puzzles | 34% | 24% |
| LMArena Hard Prompts | 1481 | 1451 |
| DTBench | 94.9% | 90.1% |
| LMCA | 57.5% | 38.7% |
| Epoch Capabilities Index | 158.3 | 152.01 |
| ForecastBench | 59.9 | 61.4 |
| SimpleBench | 64.8% | — |
| CritPt | 20.9% | — |
| EnigmaEval | 23.5% | — |
| Thematic Generalization | — | 63.8% |
| EBR-Bench | 28.6% | — |
| Mystery Game Puzzles | 36% | — |
| Surface Evolver Bench | 87.5% | — |
| Bench to the Future 3 | 0.14 | — |

## Math

- Claude Opus 4.8: 78.2 (#11)
- Grok 4.20 (Non-Reasoning): 48.0 (#54)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| FrontierMath (Tiers 1-3) | 80% | 44.9% |
| FrontierMath Tier 4 | 56.1% | 17.1% |
| OTIS Mock AIME 2024-2025 | 98.3% | 92.2% |
| ProofBench | 69% | 14% |
| LMArena Math | 1487 | 1455 |
| MathArena Final-Answer Competitions | 91.8% | — |
| FrontierMath (Feb 2025 set) | 47.2% | — |
| FrontierMath Tier 4 (v1) | 31.3% | — |

## Knowledge

- Claude Opus 4.8: 61.3 (#26)
- Grok 4.20 (Non-Reasoning): 52.8 (#54)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| GPQA Diamond | 91% | 89.3% |
| SimpleQA Verified | 53% | 30.2% |
| LMArena Expert | 1501 | 1440 |

## Multimodal

- Claude Opus 4.8: 43.2 (#20)
- Grok 4.20 (Non-Reasoning): 33.2 (#88)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Vision | 1295 | 1263 |
| Blueprint-Bench 2 | 14.5% | 0% |
| LMArena Document | 1475 | 1416 |
| Furniture Assembly | 42.5% | — |

## Multilingual

- Claude Opus 4.8: 55.4 (#31)
- Grok 4.20 (Non-Reasoning): 54.7 (#38)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Non-English | 1450 | 1440 |
| LMArena Chinese | 1509 | 1481 |
| LMArena French | 1482 | 1477 |
| LMArena German | 1470 | 1463 |
| LMArena Japanese | 1440 | 1450 |
| LMArena Korean | 1432 | 1417 |
| LMArena Russian | 1476 | 1457 |
| LMArena Spanish | 1470 | 1442 |

## Instruction Following

- Claude Opus 4.8: 77.6 (#22)
- Grok 4.20 (Non-Reasoning): 75.0 (#79)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Instruction Following | 1476 | 1420 |

## Long Context

- Claude Opus 4.8: 45.4 (#37)
- Grok 4.20 (Non-Reasoning): 45.4 (#33)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Longer Query | 1482 | 1436 |
| CL-bench | — | 22.2% |
| CL-bench Life | — | 11.9% |

## Writing & Preference

- Claude Opus 4.8: 72.1 (#17)
- Grok 4.20 (Non-Reasoning): 65.9 (#42)

| Benchmark | Claude Opus 4.8 | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Text | 1460 | 1451 |
| LMArena Creative Writing | 1453 | 1439 |
| EQ-Bench Creative Writing | 1840 | 1574 |
| LMArena Multi-Turn | 1476 | 1456 |
| EQ-Bench 4 | 1281 | — |

## FAQ

### Is Claude Opus 4.8 better than Grok 4.20 (Non-Reasoning)?

Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 48.5 on the Noometry Index. Grok 4.20 (Non-Reasoning) costs 6.4× less per token, which makes it the better buy when Claude Opus 4.8's lead doesn't matter for your workload.

### Which is cheaper, Claude Opus 4.8 or Grok 4.20 (Non-Reasoning)?

Grok 4.20 (Non-Reasoning) is cheaper. It lists at $1.25 per million input tokens and $2.50 per million output tokens; Claude Opus 4.8 lists at $5 and $25.

### Is Claude Opus 4.8 or Grok 4.20 (Non-Reasoning) better for coding?

Claude Opus 4.8 scores higher on coding benchmarks: 60.2 versus 41.8 in the Noometry coding category.

### Which has the bigger context window?

Both accept 1M tokens.

### How many benchmarks do Claude Opus 4.8 and Grok 4.20 (Non-Reasoning) share?

42 benchmarks have published results for both models. Claude Opus 4.8 has 65 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.