# Claude 2.1 vs Claude Opus 4

> Claude Opus 4 is the stronger model overall, scoring 43.1 to 25.2 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-2-1-vs-claude-opus-4
- Last updated: 2026-10-11
- Shared benchmarks: 6

## Summary

- They share 6 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and Claude Opus 4 in 4 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 4 leads 42.0 to 10.2.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 64.4% for Claude Opus 4.

## Snapshot

| | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 25.2 | 43.1 |
| Rank | 345 | 100 |
| Context | — | 200K |
| Input $/M | — | $15 |
| Output $/M | — | $75 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 26.2 (#327)
- Claude Opus 4: 47.2 (#62)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| WeirdML | 7.1% | 43.7% |
| SWE-bench Verified | — | 70.7% |
| SWE-bench Verified (bash only) | — | 67.6% |
| Aider Polyglot | — | 72% |
| GSO | — | 6.9% |
| LMArena Coding | — | 1442 |
| AlgoTune | — | 1.33 |

## Agentic & Tool Use

- Claude 2.1: —
- Claude Opus 4: 34.8 (#42)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| Cybench | — | 38% |
| DeepResearch Bench | — | 46.8% |
| LMArena Search | — | 1127 |
| METR Time Horizons | — | 63.9% |

## Reasoning

- Claude 2.1: 21.4 (#221)
- Claude Opus 4: 27.3 (#121)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| DTBench | 51% | 81.6% |
| Epoch Capabilities Index | 119.27 | 142.67 |
| ForecastBench | 54.2 | 61.1 |
| ARC-AGI-2 | — | 8.6% |
| SimpleBench | — | 58.8% |
| Kagi LLM Benchmark | — | 74.3% |
| ARC-AGI-1 | — | 35.7% |
| CritPt | — | 0.3% |
| EnigmaEval | — | 5.6% |
| LMArena Hard Prompts | — | 1399 |
| LMCA | — | 37.4% |

## Math

- Claude 2.1: 10.2 (#315)
- Claude Opus 4: 42.0 (#86)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | 64.4% |
| Omni-MATH | — | 61.6% |
| LMArena Math | — | 1390 |
| MATH Level 5 | — | 85% |
| FrontierMath (Feb 2025 set) | — | 4.5% |
| FrontierMath Tier 4 (v1) | — | 4.2% |

## Knowledge

- Claude 2.1: 15.4 (#292)
- Claude Opus 4: 44.0 (#88)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| GPQA Diamond | 33% | 76.3% |
| Humanity's Last Exam | — | 10.7% |
| MMLU-Pro | — | 87.5% |
| Confabulations | — | 15.9% |
| Vectara Hallucination Rate | — | 12% |
| GPQA (HELM) | — | 70.8% |
| LMArena Expert | — | 1386 |
| MMLU | 73.5% | — |

## Multimodal

- Claude 2.1: —
- Claude Opus 4: 31.5 (#106)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| LMArena Vision | — | 1192 |
| GeoBench | — | 49% |
| VPCT | — | 38% |

## Multilingual

- Claude 2.1: —
- Claude Opus 4: 48.8 (#138)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| LMArena Non-English | — | 1362 |
| LMArena Chinese | — | 1386 |
| LMArena French | — | 1372 |
| LMArena German | — | 1391 |
| LMArena Japanese | — | 1331 |
| LMArena Korean | — | 1321 |
| LMArena Russian | — | 1392 |
| LMArena Spanish | — | 1389 |

## Instruction Following

- Claude 2.1: —
- Claude Opus 4: 77.1 (#28)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| IFEval | — | 91.8% |
| LMArena Instruction Following | — | 1406 |

## Long Context

- Claude 2.1: —
- Claude Opus 4: 39.6 (#172)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| Fiction.LiveBench | — | 61.1% |
| LMArena Longer Query | — | 1422 |

## Writing & Preference

- Claude 2.1: —
- Claude Opus 4: 61.2 (#89)

| Benchmark | Claude 2.1 | Claude Opus 4 |
|---|---|---|
| LMArena Text | — | 1377 |
| LMArena Creative Writing | — | 1387 |
| Short-Story Creative Writing | — | 83.6% |
| EQ-Bench Creative Writing | — | 1580 |
| WildBench | — | 85.2% |
| LMArena Multi-Turn | — | 1396 |

## FAQ

### Is Claude 2.1 better than Claude Opus 4?

Claude Opus 4 is the stronger model overall, scoring 43.1 to 25.2 on the Noometry Index.

### Is Claude 2.1 or Claude Opus 4 better for coding?

Claude Opus 4 scores higher on coding benchmarks: 47.2 versus 26.2 in the Noometry coding category.

### How many benchmarks do Claude 2.1 and Claude Opus 4 share?

6 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and Claude Opus 4 has 56.