# Qwen3.5 Plus vs Qwen3 8B

> Qwen3.5 Plus is the stronger model overall, scoring 42.3 to 33.3 on the Noometry Index. Qwen3 8B costs 2.9× less per token, which makes it the better buy when Qwen3.5 Plus's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/qwen3-5-plus-vs-qwen3-8b
- Last updated: 2026-10-10
- Shared benchmarks: 7

## Summary

- They share 7 benchmarks with published results for both. Qwen3.5 Plus scores higher in 4 categories and Qwen3 8B in 0 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Qwen3.5 Plus leads 32.0 to 16.1.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 86.7% for Qwen3.5 Plus and 56.1% for Qwen3 8B.
- Qwen3 8B is cheaper at $0.18 / $0.70 per million input/output tokens, against $0.40 / $2.40 for Qwen3.5 Plus.
- Qwen3.5 Plus accepts more context: 1M tokens versus 131K.
- Qwen3 8B has downloadable open weights; the other is API-only.

## Snapshot

| | Qwen3.5 Plus | Qwen3 8B |
|---|---|---|
| Provider | Alibaba (Qwen) | Alibaba (Qwen) |
| Noometry Index | 42.3 | 33.3 |
| Rank | 103 | 237 |
| Context | 1M | 131K |
| Input $/M | $0.40 | $0.18 |
| Output $/M | $2.40 | $0.70 |
| Weights | Proprietary | Open |

## Coding

- Qwen3.5 Plus: —
- Qwen3 8B: 33.4 (#245)

| Benchmark | Qwen3.5 Plus | Qwen3 8B |
|---|---|---|
| SciCode | — | 22.6% |
| ALE-Bench | 621.92 | — |

## Agentic & Tool Use

- Qwen3.5 Plus: —
- Qwen3 8B: 29.9 (#71)

| Benchmark | Qwen3.5 Plus | Qwen3 8B |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 42.6% |
| Vending-Bench 2 | 0.54 | — |

## Reasoning

- Qwen3.5 Plus: 32.0 (#67)
- Qwen3 8B: 16.1 (#299)

| Benchmark | Qwen3.5 Plus | Qwen3 8B |
|---|---|---|
| Chess Puzzles | 22% | 5% |
| DTBench | 80.5% | 59.7% |
| LMCA | 36.4% | 8.8% |
| Epoch Capabilities Index | 146.79 | 136.17 |
| CritPt | — | 0% |
| Mystery Game Puzzles | 17% | — |

## Math

- Qwen3.5 Plus: 47.9 (#55)
- Qwen3 8B: 33.3 (#176)

| Benchmark | Qwen3.5 Plus | Qwen3 8B |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 86.7% | 56.1% |
| FrontierMath (Feb 2025 set) | 21% | — |
| FrontierMath Tier 4 (v1) | 2.1% | — |

## Knowledge

- Qwen3.5 Plus: 46.0 (#78)
- Qwen3 8B: 36.1 (#164)

| Benchmark | Qwen3.5 Plus | Qwen3 8B |
|---|---|---|
| GPQA Diamond | 84.8% | 56.8% |
| Vectara Hallucination Rate | 10.7% | 4.8% |
| SimpleQA Verified | 25.4% | — |

## Long Context

- Qwen3.5 Plus: 42.9 (#109)
- Qwen3 8B: 37.8 (#205)

| Benchmark | Qwen3.5 Plus | Qwen3 8B |
|---|---|---|
| Fiction.LiveBench | — | 62.1% |
| CL-bench | 19.8% | — |
| CL-bench Life | 12.4% | — |

## FAQ

### Is Qwen3.5 Plus better than Qwen3 8B?

Qwen3.5 Plus is the stronger model overall, scoring 42.3 to 33.3 on the Noometry Index. Qwen3 8B costs 2.9× less per token, which makes it the better buy when Qwen3.5 Plus's lead doesn't matter for your workload.

### Which is cheaper, Qwen3.5 Plus or Qwen3 8B?

Qwen3 8B is cheaper. It lists at $0.18 per million input tokens and $0.70 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 131K.

### How many benchmarks do Qwen3.5 Plus and Qwen3 8B share?

7 benchmarks have published results for both models. Qwen3.5 Plus has 15 scored results on Noometry and Qwen3 8B has 11.