# Claude 2.1 vs DeepSeek V4.1 Flash

> DeepSeek V4.1 Flash is the stronger model overall, scoring 52.8 to 25.2 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-2-1-vs-deepseek-v4-1-flash
- Last updated: 2026-10-12
- Shared benchmarks: 4

## Summary

- They share 4 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and DeepSeek V4.1 Flash in 4 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in math, where DeepSeek V4.1 Flash leads 66.7 to 10.2.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 98.3% for DeepSeek V4.1 Flash.
- DeepSeek V4.1 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| Provider | Anthropic | DeepSeek |
| Noometry Index | 25.2 | 52.8 |
| Rank | 345 | 38 |
| Context | — | 1M |
| Input $/M | — | $0.15 |
| Output $/M | — | $0.60 |
| Weights | Proprietary | Open |

## Coding

- Claude 2.1: 26.2 (#327)
- DeepSeek V4.1 Flash: 52.9 (#32)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena WebDev | — | 1619 |
| SciCode | — | 51.9% |
| WeirdML | 7.1% | — |
| LMArena Coding | — | 1506 |
| ALE-Bench | — | 1,092 |

## Agentic & Tool Use

- Claude 2.1: —
- DeepSeek V4.1 Flash: 31.2 (#69)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| APEX-Agents | — | 39.5% |
| GDP.pdf | — | 19.8% |

## Reasoning

- Claude 2.1: 21.4 (#221)
- DeepSeek V4.1 Flash: 50.2 (#36)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| DTBench | 51% | 89.9% |
| Epoch Capabilities Index | 119.27 | 154.9 |
| NYT Connections (extended) | — | 89.6% |
| CritPt | — | 14.3% |
| LMArena Hard Prompts | — | 1483 |
| Mystery Game Puzzles | — | 43% |
| LMCA | — | 47% |
| Surface Evolver Bench | — | 46.3% |
| ForecastBench | 54.2 | — |

## Math

- Claude 2.1: 10.2 (#315)
- DeepSeek V4.1 Flash: 66.7 (#25)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | 98.3% |
| FrontierMath (Tiers 1-3) | — | 67.4% |
| FrontierMath Tier 4 | — | 26.8% |
| ProofBench | — | 54% |
| LMArena Math | — | 1477 |

## Knowledge

- Claude 2.1: 15.4 (#292)
- DeepSeek V4.1 Flash: 57.9 (#38)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| GPQA Diamond | 33% | 89.8% |
| LMArena Expert | — | 1506 |
| MMLU | 73.5% | — |

## Multimodal

- Claude 2.1: —
- DeepSeek V4.1 Flash: 39.1 (#61)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Vision | — | 1277 |
| Furniture Assembly | — | 34.2% |

## Multilingual

- Claude 2.1: —
- DeepSeek V4.1 Flash: 55.0 (#35)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Non-English | — | 1448 |
| LMArena Chinese | — | 1497 |
| LMArena French | — | 1452 |
| LMArena German | — | 1484 |
| LMArena Japanese | — | 1412 |
| LMArena Korean | — | 1452 |
| LMArena Russian | — | 1471 |
| LMArena Spanish | — | 1459 |

## Instruction Following

- Claude 2.1: —
- DeepSeek V4.1 Flash: 77.3 (#26)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Instruction Following | — | 1474 |

## Long Context

- Claude 2.1: —
- DeepSeek V4.1 Flash: 45.2 (#47)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Longer Query | — | 1475 |

## Writing & Preference

- Claude 2.1: —
- DeepSeek V4.1 Flash: 65.4 (#48)

| Benchmark | Claude 2.1 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Text | — | 1462 |
| LMArena Creative Writing | — | 1435 |
| EQ-Bench Creative Writing | — | 1540 |
| LMArena Multi-Turn | — | 1457 |

## FAQ

### Is Claude 2.1 better than DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash is the stronger model overall, scoring 52.8 to 25.2 on the Noometry Index.

### Is Claude 2.1 or DeepSeek V4.1 Flash better for coding?

DeepSeek V4.1 Flash scores higher on coding benchmarks: 52.9 versus 26.2 in the Noometry coding category.

### How many benchmarks do Claude 2.1 and DeepSeek V4.1 Flash share?

4 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and DeepSeek V4.1 Flash has 37.