Claude Opus 4.1 vs Qwen3.5-Flash
Updated October 21, 2026. 48 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick Claude Opus 4.1 for coding: it scores 27.2 on the Vibe Coding Index against 6.2 for Qwen3.5-Flash.
Pick Qwen3.5-Flash when output tokens cost 288.5x less, or when the context window is larger, 1M against 200K tokens.
- Shared results
- 48
- Claude Opus 4.1 only
- 23
- Qwen3.5-Flash only
- 7
- Like-for-like categories
- 6 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, four public coding benchmarks
Claude Opus 4.1
Claude Opus 4.1 scores 27.2 against 6.2.
One benchmark behind each score
Intelligence
AA Intelligence Index
No call
Only Claude Opus 4.1 has a AA Intelligence Index result, 22.8.
Directional only
Reasoning
GPQA Diamond
Qwen3.5-Flash
Qwen3.5-Flash leads, 82.8% against 76.3%.
Same board, both measured
Math
AIME
Qwen3.5-Flash
Qwen3.5-Flash leads, 92.5% against 78.2%.
Same board, both measured
Knowledge
MMLU Pro
Claude Opus 4.1
Claude Opus 4.1 leads, 87.9% against 84.1%.
Same board, both measured
Web design
Design Arena: websites
No call
Only Claude Opus 4.1 has a Design Arena: websites result, 1177.
Directional only
Long documents
Listed context window
Qwen3.5-Flash
Qwen3.5-Flash takes 1M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Qwen3.5-Flash
Claude Opus 4.1 $0.052, Qwen3.5-Flash $0.0002 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Qwen3.5-Flash has the number, $0.40.
Directional only
At a glance
- Coding index
- Claude Opus 4.1 27.2 from 1 benchmark, Qwen3.5-Flash 6.2 from 1 benchmark.
- Widest category
- Coding, 14.7 points apart on average over 5 shared benchmarks.
- Widest single gap
- LMArena WebDev: Claude Opus 4.1 1390 against Qwen3.5-Flash 1244, 20.9 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.1 $75.00 against Qwen3.5-Flash $0.26 per million output tokens, 288.5x apart.
- Context window
- Claude Opus 4.1 takes 200K tokens, Qwen3.5-Flash 1M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Claude Opus 4.1 | Bars | Qwen3.5-Flash | Ties |
|---|---|---|---|---|
| Coding | 4 | 1 | ||
| Intelligence | 1 | 0 | ||
| Reasoning | 4 | 3 | ||
| Math | 2 | 3 | ||
| Knowledge | 7 | 2 | ||
| General | 18 | 3 | ||
| All shared boards | 36 | 12 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index41
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| LMArena WebDev | 1390 | 1244 | Claude Opus 4.1 |
| LiveCodeBench (Vals AI) | 66.5% | 83.3% | Qwen3.5-Flash |
| SWE-bench Verified (Vals AI) | Not measured | 64.4% | Only Qwen3.5-Flash measured |
| Terminal-Bench | 38.0% | Not measured | Only Claude Opus 4.1 measured |
| WeirdML | 45.9% | Not measured | Only Claude Opus 4.1 measured |
| Cybench | 42.0% | Not measured | Only Claude Opus 4.1 measured |
| ALE-Bench | Not measured | 265.9 | Only Qwen3.5-Flash measured |
| LMArena Text: coding | 1479 | 1412 | Claude Opus 4.1 |
| LMArena Text: software and IT | 1456 | 1416 | Claude Opus 4.1 |
| LMArena WebDev: React | Not measured | 1229 | Only Qwen3.5-Flash measured |
| LMArena WebDev: HTML | 1399 | 1291 | Claude Opus 4.1 |
| Neither model has a result on the other 27 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.8 | Not measured | Only Claude Opus 4.1 measured |
| Epoch Capabilities Index | 144.1 | 143.5 | Claude Opus 4.1 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index3 boards, none shared
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| METR time horizons | 66.8% | Not measured | Only Claude Opus 4.1 measured |
| GDPval | 43.6% | Not measured | Only Claude Opus 4.1 measured |
| DeepResearch Bench | 48.3% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 36 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index43
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| GPQA Diamond | 76.3% | 82.8% | Qwen3.5-Flash |
| MMMU Pro (Vals AI) | 77.5% | 81.9% | Qwen3.5-Flash |
| GPQA Diamond (Epoch AI run) | 77.3% | 82.3% | Qwen3.5-Flash |
| SimpleBench | 60.0% | Not measured | Only Claude Opus 4.1 measured |
| Chess puzzles | Not measured | 14.0% | Only Qwen3.5-Flash measured |
| Mystery game puzzles | 21.0% | 20.0% | Claude Opus 4.1 |
| EBR-bench | 7.9% | Not measured | Only Claude Opus 4.1 measured |
| VPCT | 35.0% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: hard prompts | 1442 | 1403 | Claude Opus 4.1 |
| LMArena Text: expert | 1438 | 1407 | Claude Opus 4.1 |
| LMArena Text: hard prompts in English | 1451 | 1409 | Claude Opus 4.1 |
| Neither model has a result on the other 10 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index23
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| AIME | 78.2% | 92.5% | Qwen3.5-Flash |
| MATH 500 (Vals AI) | 95.4% | Not measured | Only Claude Opus 4.1 measured |
| MGSM (Vals AI) | 94.4% | Not measured | Only Claude Opus 4.1 measured |
| OTIS Mock AIME | 68.9% | 84.4% | Qwen3.5-Flash |
| FrontierMath, tiers 1 to 3 | 12.6% | 18.2% | Qwen3.5-Flash |
| FrontierMath, tier 4 | 2.4% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: math | 1431 | 1407 | Claude Opus 4.1 |
| LMArena Text: mathematical work | 1434 | 1413 | Claude Opus 4.1 |
| Neither model has a result on the other 5 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index72
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| MMLU Pro | 87.9% | 84.1% | Claude Opus 4.1 |
| LegalBench (Vals AI) | 83.5% | 84.3% | Qwen3.5-Flash |
| CaseLaw (Vals AI) | Not measured | 56.0% | Only Qwen3.5-Flash measured |
| CorpFin (Vals AI) | Not measured | 63.6% | Only Qwen3.5-Flash measured |
| TaxEval (Vals AI) | 73.7% | 72.2% | Claude Opus 4.1 |
| MortgageTax (Vals AI) | 61.1% | 67.4% | Qwen3.5-Flash |
| MedQA (Vals AI) | 93.6% | Not measured | Only Claude Opus 4.1 measured |
| MedCode (Vals AI) | 47.2% | 33.0% | Claude Opus 4.1 |
| SimpleQA Verified | Not measured | 20.3% | Only Qwen3.5-Flash measured |
| LMArena Text: science | 1422 | 1415 | Claude Opus 4.1 |
| LMArena Text: medicine and healthcare | 1416 | 1407 | Claude Opus 4.1 |
| LMArena Text: legal and government | 1421 | 1398 | Claude Opus 4.1 |
| LMArena Text: business and finance | 1406 | 1394 | Claude Opus 4.1 |
| Neither model has a result on the other 4 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| Design Arena: websites | 1177 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: UI components | 1164 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: game dev | 1172 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: data viz | 1166 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: 3D | 1153 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: all code categories | 1171 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: SVG | 1152 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: ASCII art | 1167 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index183
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 31.4% | 42.5% | Qwen3.5-Flash |
| MedScribe (Vals AI) | 73.9% | 70.6% | Claude Opus 4.1 |
| DTBench | 80.0% | 82.9% | Qwen3.5-Flash |
| LMCA | 37.1% | 29.1% | Claude Opus 4.1 |
| Creative writing (Lech Mazur) | 84.7% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text | 1419 | 1397 | Claude Opus 4.1 |
| LMArena Text: instruction following | 1435 | 1374 | Claude Opus 4.1 |
| LMArena Text: creative writing | 1412 | 1343 | Claude Opus 4.1 |
| LMArena Text: English | 1433 | 1404 | Claude Opus 4.1 |
| LMArena Text: non-English | 1405 | 1385 | Claude Opus 4.1 |
| LMArena Text: Chinese | 1427 | 1445 | Qwen3.5-Flash |
| LMArena Text: German | 1413 | 1390 | Claude Opus 4.1 |
| LMArena Text: Japanese | 1377 | 1369 | Claude Opus 4.1 |
| LMArena Text: Korean | 1381 | 1344 | Claude Opus 4.1 |
| LMArena Text: French | 1433 | 1413 | Claude Opus 4.1 |
| LMArena Text: Spanish | 1448 | 1400 | Claude Opus 4.1 |
| LMArena Text: Russian | 1422 | 1380 | Claude Opus 4.1 |
| LMArena Text: Polish | 1413 | 1376 | Claude Opus 4.1 |
| LMArena Text: multi-turn | 1444 | 1393 | Claude Opus 4.1 |
| LMArena Text: longer queries | 1455 | 1392 | Claude Opus 4.1 |
| LMArena Text: writing and language | 1418 | 1369 | Claude Opus 4.1 |
| LMArena Text: entertainment and media | 1398 | 1347 | Claude Opus 4.1 |
| Neither model has a result on the other 24 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.1 | Qwen3.5-Flash | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Qwen3.5-Flash costs less
Repository review
50K input + 3K output tokens
Qwen3.5-Flash costs less
Agent loop
200K input + 10K output tokens
Qwen3.5-Flash costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Anthropic Claude Opus 4.1 | Qwen3.5-Flash |
|---|---|---|
| Maker | Anthropic | Qwen |
| Weights | No public weights listed | No public weights listed |
| Released | August 5, 2025 | February 25, 2026 |
| Context window | 200K | 1M |
| Input $/Mtok | $15.00 | $0.065 |
| Output $/Mtok | $75.00 | $0.26 |
| Coding index | 27.2 | 6.2 |
| Independent measurements behind it | 1 | 1 |
| Cost per solved task | Not computable | $0.40 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.1 better than Qwen3.5-Flash for coding?
Pick Claude Opus 4.1 for coding: it scores 27.2 on the Vibe Coding Index against 6.2 for Qwen3.5-Flash. Pick Qwen3.5-Flash when output tokens cost 288.5x less, or when the context window is larger, 1M against 200K tokens.
Which is cheaper, Claude Opus 4.1 or Qwen3.5-Flash?
Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; Qwen3.5-Flash costs $0.065 and $0.26. Cost per solved task is known for Qwen3.5-Flash only.
Which has the bigger context window, Claude Opus 4.1 or Qwen3.5-Flash?
Qwen3.5-Flash, with 1M tokens against 200K.
How many benchmarks is the Claude Opus 4.1 vs Qwen3.5-Flash comparison based on?
48 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and Qwen3.5-Flash's on 1. Where only one model has a result, the page says so instead of naming a winner.