Qwen3.5 Plus 2026-04-20 vs Qwen3.8 27B
Qwen3.8 27B leads Qwen3.5 Plus 2026-04-20 on coding, 74.2 to 39.5 on the Vibe Coding Index, and Qwen3.5 Plus 2026-04-20 costs 1.4x less per output token ($1.80 vs $2.55 per million). Updated October 22, 2026; 12 benchmarks have a result for both.
Qwen3.5 Plus 2026-04-20 or Qwen3.8 27B: which to pick
Pick Qwen3.8 27B for coding: it scores 74.2 on the Vibe Coding Index against 39.5 for Qwen3.5 Plus 2026-04-20.
Pick Qwen3.5 Plus 2026-04-20 for output tokens 1.4x cheaper ($1.80 vs $2.55 per million) and work measured by LiveCodeBench (Vals AI) or MMLU Pro, where it leads.
- Shared results
- 12
- Qwen3.5 Plus 2026-04-20 only
- 13
- Qwen3.8 27B only
- 73
- Like-for-like categories
- 5 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
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, six public coding benchmarks
Qwen3.8 27B
Qwen3.8 27B scores 74.2 against 39.5.
2 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
No call
Only Qwen3.8 27B has a AA Intelligence Index result, 33.7.
Directional only
Agentic work
AA Agentic Index
No call
Only Qwen3.8 27B has a AA Agentic Index result, 45.8.
Directional only
Reasoning
GPQA Diamond
Qwen3.8 27B
Qwen3.8 27B leads, 88.9% against 87.4%.
Same board, both measured
Math
AIME
No call
Only Qwen3.5 Plus 2026-04-20 has a AIME result, 86.0%.
Directional only
Knowledge
MMLU Pro
Qwen3.5 Plus 2026-04-20
Qwen3.5 Plus 2026-04-20 leads, 87.2% against 84.3%.
Same board, both measured
Long documents
Listed context window
No call
Both take 1M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Qwen3.5 Plus 2026-04-20
Qwen3.5 Plus 2026-04-20 $0.0012, Qwen3.8 27B $0.0017 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Qwen3.8 27B
Qwen3.5 Plus 2026-04-20 $1.35, Qwen3.8 27B $1.26.
Published attempt cost and pass rate
At a glance
- Coding index
- Qwen3.5 Plus 2026-04-20 39.5 from 2 benchmarks, Qwen3.8 27B 74.2 from 4 benchmarks.
- Widest category
- Reasoning, 31.3 points apart on average over 2 shared benchmarks.
- Widest single gap
- MMMU Pro (Vals AI): Qwen3.5 Plus 2026-04-20 22.8% against Qwen3.8 27B 83.9%, 61.2 points apart on a 0 to 100 scale.
- Output price
- Qwen3.5 Plus 2026-04-20 $1.80 against Qwen3.8 27B $2.55 per million output tokens, 1.4x apart.
- Context window
- Both take 1M tokens.
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 | Qwen3.5 Plus 2026-04-20 | Bars | Qwen3.8 27B | Ties |
|---|---|---|---|---|
| Coding | 1 | 2 | ||
| Intelligence | 0 | 1 | ||
| Reasoning | 0 | 2 | ||
| Knowledge | 2 | 1 | ||
| General | 0 | 3 | ||
| All shared boards | 3 | 9 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index12
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 86.8% | Only Qwen3.8 27B measured |
| LMArena WebDev | Not measured | 1593 | Only Qwen3.8 27B measured |
| AA Coding Index | Not measured | 68.1 | Only Qwen3.8 27B measured |
| LiveCodeBench (Vals AI) | 85.3% | 84.0% | Qwen3.5 Plus 2026-04-20 |
| SWE-bench Verified (Vals AI) | 71.2% | 86.0% | Qwen3.8 27B |
| Vibe Code Bench (Vals AI) | 15.7% | 64.8% | Qwen3.8 27B |
| Code migration (Vals AI) | Not measured | 14.2% | Only Qwen3.8 27B measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Qwen3.8 27B measured |
| IOI (Vals AI) | Not measured | 39.1% | Only Qwen3.8 27B measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 58.4% | Only Qwen3.8 27B measured |
| SkillsBench (Vals AI) | Not measured | 38.1% | Only Qwen3.8 27B measured |
| CyberBench (Vals AI) | Not measured | 67.8% | Only Qwen3.8 27B measured |
| SciCode | Not measured | 46.6% | Only Qwen3.8 27B measured |
| ALE-Bench | 608.9 | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text: coding | Not measured | 1483 | Only Qwen3.8 27B measured |
| LMArena Text: software and IT | Not measured | 1478 | Only Qwen3.8 27B measured |
| LMArena WebDev: React | Not measured | 1602 | Only Qwen3.8 27B measured |
| LMArena WebDev: HTML | Not measured | 1570 | Only Qwen3.8 27B measured |
| LMArena WebDev: from an image | Not measured | 1577 | Only Qwen3.8 27B measured |
| Neither model has a result on the other 24 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 33.7 | Only Qwen3.8 27B measured |
| Epoch Capabilities Index | 146.2 | 151.7 | Qwen3.8 27B |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index11 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 45.8 | Only Qwen3.8 27B measured |
| LiveBench research | Not measured | 59.4% | Only Qwen3.8 27B measured |
| LiveBench browser | Not measured | 32.0% | Only Qwen3.8 27B measured |
| LiveBench long agentic | Not measured | 27.9% | Only Qwen3.8 27B measured |
| Finance Agent (Vals AI) | Not measured | 48.5% | Only Qwen3.8 27B measured |
| Tax Agent Bench (Vals AI) | Not measured | 30.9% | Only Qwen3.8 27B measured |
| Legal Research Bench (Vals AI) | Not measured | 36.1% | Only Qwen3.8 27B measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 59.7% | Only Qwen3.8 27B measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 0.0% | Only Qwen3.8 27B measured |
| APEX-Agents | Not measured | 47.5% | Only Qwen3.8 27B measured |
| Vending-Bench 2 | $1 | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Neither model has a result on the other 31 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| GPQA Diamond | 87.4% | 88.9% | Qwen3.8 27B |
| LiveBench reasoning | Not measured | 80.0% | Only Qwen3.8 27B measured |
| MMMU Pro (Vals AI) | 22.8% | 83.9% | Qwen3.8 27B |
| GPQA Diamond (Artificial Analysis run) | Not measured | 90.5% | Only Qwen3.8 27B measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 33.9% | Only Qwen3.8 27B measured |
| GPQA Diamond (Epoch AI run) | 84.8% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| ARC-AGI | Not measured | 87.5% | Only Qwen3.8 27B measured |
| ARC-AGI-2 | Not measured | 42.4% | Only Qwen3.8 27B measured |
| Chess puzzles | 8.0% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Mystery game puzzles | 17.0% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text: hard prompts | Not measured | 1459 | Only Qwen3.8 27B measured |
| LMArena Text: expert | Not measured | 1479 | Only Qwen3.8 27B measured |
| LMArena Text: hard prompts in English | Not measured | 1461 | Only Qwen3.8 27B measured |
| LMArena Vision: diagrams | Not measured | 1285 | Only Qwen3.8 27B measured |
| LMArena Vision: homework | Not measured | 1295 | Only Qwen3.8 27B measured |
| Neither model has a result on the other 8 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| AIME | 86.0% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| OTIS Mock AIME | 86.7% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| ProofBench | Not measured | 16.0% | Only Qwen3.8 27B measured |
| LMArena Text: math | Not measured | 1455 | Only Qwen3.8 27B measured |
| LMArena Text: mathematical work | Not measured | 1458 | Only Qwen3.8 27B measured |
| Neither model has a result on the other 9 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index21
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| MMLU Pro | 87.2% | 84.3% | Qwen3.5 Plus 2026-04-20 |
| LegalBench (Vals AI) | 85.1% | 82.4% | Qwen3.5 Plus 2026-04-20 |
| CaseLaw (Vals AI) | 59.7% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| CorpFin (Vals AI) | 65.3% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| TaxEval (Vals AI) | Not measured | 70.8% | Only Qwen3.8 27B measured |
| MortgageTax (Vals AI) | 60.8% | 64.9% | Qwen3.8 27B |
| MedQA (Vals AI) | 95.2% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| MedCode (Vals AI) | Not measured | 28.7% | Only Qwen3.8 27B measured |
| SimpleQA Verified | 25.4% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text: science | Not measured | 1467 | Only Qwen3.8 27B measured |
| LMArena Text: medicine and healthcare | Not measured | 1437 | Only Qwen3.8 27B measured |
| LMArena Text: legal and government | Not measured | 1447 | Only Qwen3.8 27B measured |
| LMArena Text: business and finance | Not measured | 1438 | Only Qwen3.8 27B measured |
| Neither model has a result on the other 7 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| LiveBench design | Not measured | 75.9% | Only Qwen3.8 27B measured |
| Neither model has a result on the other 8 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | Leader |
|---|---|---|---|
| LiveBench data analysis | Not measured | 76.6% | Only Qwen3.8 27B measured |
| SAGE (Vals AI) | 30.4% | 52.4% | Qwen3.8 27B |
| MedScribe (Vals AI) | Not measured | 83.8% | Only Qwen3.8 27B measured |
| Long context reasoning (AA-LCR) | Not measured | 82.0% | Only Qwen3.8 27B measured |
| DTBench | 80.5% | 88.0% | Qwen3.8 27B |
| LMCA | 36.4% | 41.4% | Qwen3.8 27B |
| CL-bench | 19.8% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Surface Evolver Bench | Not measured | 45.0% | Only Qwen3.8 27B measured |
| CL-bench Life | 12.4% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text | Not measured | 1440 | Only Qwen3.8 27B measured |
| LMArena Text: instruction following | Not measured | 1436 | Only Qwen3.8 27B measured |
| LMArena Text: creative writing | Not measured | 1383 | Only Qwen3.8 27B measured |
| LMArena Vision | Not measured | 1269 | Only Qwen3.8 27B measured |
| LMArena Text: English | Not measured | 1448 | Only Qwen3.8 27B measured |
| LMArena Text: non-English | Not measured | 1428 | Only Qwen3.8 27B measured |
| LMArena Text: Chinese | Not measured | 1501 | Only Qwen3.8 27B measured |
| LMArena Text: German | Not measured | 1443 | Only Qwen3.8 27B measured |
| LMArena Text: Japanese | Not measured | 1387 | Only Qwen3.8 27B measured |
| LMArena Text: Korean | Not measured | 1384 | Only Qwen3.8 27B measured |
| LMArena Text: French | Not measured | 1465 | Only Qwen3.8 27B measured |
| LMArena Text: Spanish | Not measured | 1449 | Only Qwen3.8 27B measured |
| LMArena Text: Russian | Not measured | 1415 | Only Qwen3.8 27B measured |
| LMArena Text: Polish | Not measured | 1439 | Only Qwen3.8 27B measured |
| LMArena Text: multi-turn | Not measured | 1440 | Only Qwen3.8 27B measured |
| LMArena Text: longer queries | Not measured | 1448 | Only Qwen3.8 27B measured |
| LMArena Text: writing and language | Not measured | 1405 | Only Qwen3.8 27B measured |
| LMArena Text: entertainment and media | Not measured | 1393 | Only Qwen3.8 27B measured |
| LMArena Vision: English | Not measured | 1267 | Only Qwen3.8 27B measured |
| LMArena Vision: Chinese | Not measured | 1326 | Only Qwen3.8 27B measured |
| LMArena Vision: reading text | Not measured | 1281 | Only Qwen3.8 27B measured |
| LMArena Vision: humor | Not measured | 1235 | Only Qwen3.8 27B measured |
| LMArena Vision: creative writing | Not measured | 1237 | Only Qwen3.8 27B measured |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B | 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 Plus 2026-04-20 costs less
Repository review
50K input + 3K output tokens
Qwen3.5 Plus 2026-04-20 costs less
Agent loop
200K input + 10K output tokens
Qwen3.5 Plus 2026-04-20 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 | Qwen3.5 Plus 2026-04-20 | Qwen3.8 27B |
|---|---|---|
| Maker | Qwen | Qwen |
| Weights | No public weights listed | Open weights |
| Released | April 27, 2026 | August 14, 2026 |
| Context window | 1M | 1M |
| Input $/Mtok | $0.30 | $0.425 |
| Output $/Mtok | $1.80 | $2.55 |
| Coding index | 39.5 | 74.2 |
| Independent measurements behind it | 2 | 4 |
| Cost per solved task | $1.35 | $1.26 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Qwen3.5 Plus 2026-04-20 better than Qwen3.8 27B for coding?
Pick Qwen3.8 27B for coding: it scores 74.2 on the Vibe Coding Index against 39.5 for Qwen3.5 Plus 2026-04-20. Pick Qwen3.5 Plus 2026-04-20 for output tokens 1.4x cheaper ($1.80 vs $2.55 per million) and work measured by LiveCodeBench (Vals AI) or MMLU Pro, where it leads.
Which is cheaper, Qwen3.5 Plus 2026-04-20 or Qwen3.8 27B?
Qwen3.5 Plus 2026-04-20 costs $0.30 per million input tokens and $1.80 per million output tokens; Qwen3.8 27B costs $0.425 and $2.55. Per solved SWE-bench Verified task, Qwen3.5 Plus 2026-04-20 costs $1.35 and Qwen3.8 27B $1.26.
Which has the bigger context window, Qwen3.5 Plus 2026-04-20 or Qwen3.8 27B?
Neither: both take 1M tokens.
How many benchmarks is the Qwen3.5 Plus 2026-04-20 vs Qwen3.8 27B comparison based on?
12 benchmarks have a result for both models as of October 22, 2026. Qwen3.5 Plus 2026-04-20's coding index rests on 2 independent benchmarks and Qwen3.8 27B's on 4. Where only one model has a result, the page says so instead of naming a winner.