# DeepSeek-V3.1 vs Qwen3.5 Plus

> DeepSeek-V3.1 and Qwen3.5 Plus score almost the same on the Noometry Index (42.2 vs 42.3), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/deepseek-v3-1-vs-qwen3-5-plus
- Last updated: 2026-10-10
- Shared benchmarks: 4

## Summary

- They share 4 benchmarks with published results for both. DeepSeek-V3.1 scores higher in 0 categories and Qwen3.5 Plus in 4 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in math, where Qwen3.5 Plus leads 47.9 to 36.1.
- The biggest single-benchmark swing is LMCA: 24.3% for DeepSeek-V3.1 and 36.4% for Qwen3.5 Plus.
- DeepSeek-V3.1 is cheaper at $0.25 / $0.95 per million input/output tokens, against $0.40 / $2.40 for Qwen3.5 Plus.
- Qwen3.5 Plus accepts more context: 1M tokens versus 164K.
- DeepSeek-V3.1 has downloadable open weights; the other is API-only.

## Snapshot

| | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| Provider | DeepSeek | Alibaba (Qwen) |
| Noometry Index | 42.2 | 42.3 |
| Rank | 106 | 103 |
| Context | 164K | 1M |
| Input $/M | $0.25 | $0.40 |
| Output $/M | $0.95 | $2.40 |
| Weights | Open | Proprietary |

## Coding

- DeepSeek-V3.1: 39.8 (#140)
- Qwen3.5 Plus: —

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| WeirdML | 38.4% | — |
| LMArena Coding | 1417 | — |
| ALE-Bench | — | 621.92 |

## Agentic & Tool Use

- DeepSeek-V3.1: —
- Qwen3.5 Plus: —

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| Vending-Bench 2 | — | 0.54 |

## Reasoning

- DeepSeek-V3.1: 27.3 (#109)
- Qwen3.5 Plus: 32.0 (#67)

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| DTBench | 82.7% | 80.5% |
| LMCA | 24.3% | 36.4% |
| Epoch Capabilities Index | 139.92 | 146.79 |
| SimpleBench | 40% | — |
| Kagi LLM Benchmark | 53.2% | — |
| Chess Puzzles | — | 22% |
| LMArena Hard Prompts | 1417 | — |
| Mystery Game Puzzles | — | 17% |
| ForecastBench | 58 | — |

## Math

- DeepSeek-V3.1: 36.1 (#125)
- Qwen3.5 Plus: 47.9 (#55)

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| OTIS Mock AIME 2024-2025 | — | 86.7% |
| LMArena Math | 1420 | — |
| FrontierMath (Feb 2025 set) | — | 21% |
| FrontierMath Tier 4 (v1) | — | 2.1% |

## Knowledge

- DeepSeek-V3.1: 43.0 (#86)
- Qwen3.5 Plus: 46.0 (#78)

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| Vectara Hallucination Rate | 5.5% | 10.7% |
| GPQA Diamond | — | 84.8% |
| SimpleQA Verified | — | 25.4% |
| LMArena Expert | 1403 | — |

## Multilingual

- DeepSeek-V3.1: 51.8 (#100)
- Qwen3.5 Plus: —

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| LMArena Non-English | 1400 | — |
| LMArena Chinese | 1470 | — |
| LMArena French | 1447 | — |
| LMArena German | 1412 | — |
| LMArena Japanese | 1374 | — |
| LMArena Korean | 1337 | — |
| LMArena Russian | 1405 | — |
| LMArena Spanish | 1429 | — |

## Instruction Following

- DeepSeek-V3.1: 74.1 (#105)
- Qwen3.5 Plus: —

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| LMArena Instruction Following | 1400 | — |

## Long Context

- DeepSeek-V3.1: 36.3 (#227)
- Qwen3.5 Plus: 42.9 (#109)

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| Fiction.LiveBench | 52.8% | — |
| CL-bench | — | 19.8% |
| CL-bench Life | — | 12.4% |
| LMArena Longer Query | 1422 | — |

## Writing & Preference

- DeepSeek-V3.1: 60.5 (#93)
- Qwen3.5 Plus: —

| Benchmark | DeepSeek-V3.1 | Qwen3.5 Plus |
|---|---|---|
| LMArena Text | 1420 | — |
| LMArena Creative Writing | 1401 | — |
| EQ-Bench Creative Writing | 1436 | — |
| LMArena Multi-Turn | 1408 | — |

## FAQ

### Is DeepSeek-V3.1 better than Qwen3.5 Plus?

DeepSeek-V3.1 and Qwen3.5 Plus score almost the same on the Noometry Index (42.2 vs 42.3), so choose on price, context window or the category you care about most.

### Which is cheaper, DeepSeek-V3.1 or Qwen3.5 Plus?

DeepSeek-V3.1 is cheaper. It lists at $0.25 per million input tokens and $0.95 per million output tokens; Qwen3.5 Plus lists at $0.40 and $2.40.

### Which has the bigger context window?

Qwen3.5 Plus does, with 1M tokens against 164K.

### How many benchmarks do DeepSeek-V3.1 and Qwen3.5 Plus share?

4 benchmarks have published results for both models. DeepSeek-V3.1 has 27 scored results on Noometry and Qwen3.5 Plus has 15.