Model comparison
Claude Sonnet 5 vs Qwen3.5-Flash
Claude Sonnet 5 is the stronger model overall, scoring 54.5 to 42.3 on the Noometry Index. Qwen3.5-Flash costs 23× less per token, which makes it the better buy when Claude Sonnet 5's lead doesn't matter for your workload.
Last verified . 29 shared benchmarks.
Alibaba (Qwen)Summary
- They share 29 benchmarks with published results for both. Claude Sonnet 5 scores higher in 8 categories and Qwen3.5-Flash in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5 leads 66.1 to 36.3.
- The biggest single-benchmark swing is FrontierMath (Tiers 1-3): 65.6% for Claude Sonnet 5 and 18.2% for Qwen3.5-Flash.
- Qwen3.5-Flash is cheaper at $0.10 / $0.40 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.
Side by side
| Claude Sonnet 5 | Qwen3.5-Flash | |
|---|---|---|
| Provider | Anthropic | Alibaba (Qwen) |
| Noometry Index | 54.5 | 42.3 |
| Released | 2026-06-29 | 2026-02-23 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1M |
| Max output | 128K | 66K |
| Input $ / M tokens | $2 | $0.10 |
| Output $ / M tokens | $10 | $0.40 |
| Results tracked | 51 | 32 |
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Category by category
Coding Claude Sonnet 5 leads
Claude Sonnet 5: 55.5 (#20), Qwen3.5-Flash: 33.9 (#234)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| LMArena WebDev | 1540 | 1243 |
| LMArena Coding | 1483 | 1412 |
| ALE-Bench | 1,463 | 221.8 |
| DeepSWE | 53.8% | — |
| FrontierCode | 42.7% | — |
| CursorBench | 34.1% | — |
| SciCode | 53.6% | — |
| GSO | 37.3% | — |
| WeirdML | 68.8% | — |
Agentic & Tool Use Not comparable
Claude Sonnet 5: 42.7 (#16), Qwen3.5-Flash: —
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| Vending-Bench 2 | 6,378 | 462.69 |
| APEX-Agents | 54.5% | — |
| GBAEval | 65.3% | — |
| LMArena Search | 1194 | — |
Reasoning Claude Sonnet 5 leads
Claude Sonnet 5: 48.2 (#37), Qwen3.5-Flash: 32.9 (#63)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| Chess Puzzles | 35% | 21% |
| LMArena Hard Prompts | 1461 | 1404 |
| Mystery Game Puzzles | 35% | 20% |
| DTBench | 92.5% | 82.9% |
| LMCA | 50% | 29.1% |
| Epoch Capabilities Index | 156.34 | 143.98 |
| SimpleBench | 60.6% | — |
| NYT Connections (extended) | 75.1% | — |
| CritPt | 16.9% | — |
| Surface Evolver Bench | 60% | — |
| Bench to the Future 3 | 0.14 | — |
| ForecastBench | 61.1 | — |
Math Claude Sonnet 5 leads
Claude Sonnet 5: 66.1 (#21), Qwen3.5-Flash: 36.3 (#117)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| FrontierMath (Tiers 1-3) | 65.6% | 18.2% |
| OTIS Mock AIME 2024-2025 | 94.7% | 84.4% |
| LMArena Math | 1467 | 1407 |
| FrontierMath Tier 4 | 29.3% | — |
| ProofBench | 77% | — |
| FrontierMath (Feb 2025 set) | — | 6.2% |
| FrontierMath Tier 4 (v1) | — | 0% |
Knowledge Claude Sonnet 5 leads
Claude Sonnet 5: 55.7 (#42), Qwen3.5-Flash: 43.2 (#84)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| GPQA Diamond | 90.5% | 82.3% |
| SimpleQA Verified | 33.7% | 20.3% |
| LMArena Expert | 1491 | 1408 |
| Vectara Hallucination Rate | — | 10.5% |
Multimodal Not comparable
Claude Sonnet 5: 42.4 (#26), Qwen3.5-Flash: —
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| LMArena Vision | 1275 | — |
| Blueprint-Bench 2 | 24.9% | — |
| LMArena Document | 1466 | — |
Multilingual Claude Sonnet 5 leads
Claude Sonnet 5: 54.0 (#55), Qwen3.5-Flash: 50.7 (#116)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| LMArena Non-English | 1431 | 1385 |
| LMArena Chinese | 1475 | 1446 |
| LMArena French | 1457 | 1412 |
| LMArena German | 1448 | 1389 |
| LMArena Japanese | 1422 | 1369 |
| LMArena Korean | 1411 | 1344 |
| LMArena Russian | 1452 | 1379 |
| LMArena Spanish | 1436 | 1399 |
Instruction Following Claude Sonnet 5 leads
Claude Sonnet 5: 76.6 (#39), Qwen3.5-Flash: 72.8 (#133)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| LMArena Instruction Following | 1453 | 1374 |
Long Context Claude Sonnet 5 leads
Claude Sonnet 5: 44.8 (#53), Qwen3.5-Flash: 42.4 (#119)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| LMArena Longer Query | 1464 | 1392 |
Writing & Preference Claude Sonnet 5 leads
Claude Sonnet 5: 69.4 (#24), Qwen3.5-Flash: 58.2 (#117)
| Benchmark | Claude Sonnet 5 | Qwen3.5-Flash |
|---|---|---|
| LMArena Text | 1443 | 1397 |
| LMArena Creative Writing | 1416 | 1343 |
| LMArena Multi-Turn | 1454 | 1393 |
| EQ-Bench Creative Writing | 1794 | — |
| EQ-Bench 4 | 1236 | — |
Frequently asked questions
Is Claude Sonnet 5 better than Qwen3.5-Flash?
Claude Sonnet 5 is the stronger model overall, scoring 54.5 to 42.3 on the Noometry Index. Qwen3.5-Flash costs 23× less per token, which makes it the better buy when Claude Sonnet 5's lead doesn't matter for your workload.
Which is cheaper, Claude Sonnet 5 or Qwen3.5-Flash?
Qwen3.5-Flash is cheaper. It lists at $0.10 per million input tokens and $0.40 per million output tokens; Claude Sonnet 5 lists at $2 and $10.
Is Claude Sonnet 5 or Qwen3.5-Flash better for coding?
Claude Sonnet 5 scores higher on coding benchmarks: 55.5 versus 33.9 in the Noometry coding category.
Which has the bigger context window?
Both accept 1M tokens.
How many benchmarks do Claude Sonnet 5 and Qwen3.5-Flash share?
29 benchmarks have published results for both models. Claude Sonnet 5 has 51 scored results on Noometry and Qwen3.5-Flash has 32.