# Claude 2.1 vs Claude Opus 4.1

> Claude Opus 4.1 is the stronger model overall, scoring 40.8 to 24.9 on the Noometry Index.

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

## Summary

- They share 6 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and Claude Opus 4.1 in 4 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Claude Opus 4.1 leads 41.9 to 15.5.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 68.9% for Claude Opus 4.1.

## Snapshot

| | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 24.9 | 40.8 |
| Rank | 340 | 136 |
| Context | — | 200K |
| Input $/M | — | $15 |
| Output $/M | — | $75 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 25.8 (#322)
- Claude Opus 4.1: 44.3 (#69)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| WeirdML | 7.1% | 45.9% |
| SWE-bench Verified | — | 73.3% |
| LMArena WebDev | — | 1390 |
| LMArena Coding | — | 1479 |
| ALE-Bench | — | 674.77 |
| AlgoTune | — | 1.34 |

## Agentic & Tool Use

- Claude 2.1: —
- Claude Opus 4.1: 34.8 (#38)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| Terminal-Bench | — | 38% |
| GDPval | — | 43.6% |
| Cybench | — | 42% |
| DeepResearch Bench | — | 48.3% |
| LMArena Search | — | 1148 |
| METR Time Horizons | — | 66.8% |

## Reasoning

- Claude 2.1: 20.6 (#216)
- Claude Opus 4.1: 31.6 (#70)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| DTBench | 51% | 80% |
| Epoch Capabilities Index | 119.22 | 144.11 |
| ForecastBench | 54.2 | 62 |
| SimpleBench | — | 60% |
| Chess Puzzles | — | 7% |
| EnigmaEval | — | 7.2% |
| EBR-Bench | — | 7.9% |
| LMArena Hard Prompts | — | 1443 |
| Mystery Game Puzzles | — | 21% |
| LMCA | — | 37.1% |

## Math

- Claude 2.1: 9.6 (#309)
- Claude Opus 4.1: 22.0 (#267)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | 68.9% |
| FrontierMath (Tiers 1-3) | — | 12.6% |
| FrontierMath Tier 4 | — | 2.4% |
| LMArena Math | — | 1430 |
| FrontierMath (Feb 2025 set) | — | 7.2% |
| FrontierMath Tier 4 (v1) | — | 4.2% |

## Knowledge

- Claude 2.1: 15.5 (#287)
- Claude Opus 4.1: 41.9 (#93)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| GPQA Diamond | 33% | 77.3% |
| Humanity's Last Exam | — | 11.5% |
| Confabulations | — | 17.1% |
| Vectara Hallucination Rate | — | 11.8% |
| LMArena Expert | — | 1439 |
| MMLU | 73.5% | — |

## Multimodal

- Claude 2.1: —
- Claude Opus 4.1: 26.2 (#114)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| VPCT | — | 35% |

## Multilingual

- Claude 2.1: —
- Claude Opus 4.1: 52.1 (#90)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| LMArena Non-English | — | 1405 |
| LMArena Chinese | — | 1427 |
| LMArena French | — | 1432 |
| LMArena German | — | 1412 |
| LMArena Japanese | — | 1378 |
| LMArena Korean | — | 1381 |
| LMArena Russian | — | 1421 |
| LMArena Spanish | — | 1448 |

## Instruction Following

- Claude 2.1: —
- Claude Opus 4.1: 75.8 (#53)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| LMArena Instruction Following | — | 1436 |

## Long Context

- Claude 2.1: —
- Claude Opus 4.1: 44.5 (#60)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| LMArena Longer Query | — | 1455 |

## Writing & Preference

- Claude 2.1: —
- Claude Opus 4.1: 62.6 (#70)

| Benchmark | Claude 2.1 | Claude Opus 4.1 |
|---|---|---|
| LMArena Text | — | 1419 |
| LMArena Creative Writing | — | 1412 |
| Short-Story Creative Writing | — | 84.7% |
| LMArena Multi-Turn | — | 1444 |

## FAQ

### Is Claude 2.1 better than Claude Opus 4.1?

Claude Opus 4.1 is the stronger model overall, scoring 40.8 to 24.9 on the Noometry Index.

### Is Claude 2.1 or Claude Opus 4.1 better for coding?

Claude Opus 4.1 scores higher on coding benchmarks: 44.3 versus 25.8 in the Noometry coding category.

### How many benchmarks do Claude 2.1 and Claude Opus 4.1 share?

6 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and Claude Opus 4.1 has 48.