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gpt-oss-20b vs Qwen3.5-27B

Qwen3.5-27B leads gpt-oss-20b on the Artificial Analysis Intelligence Index, 22.9 to 10.0, and gpt-oss-20b costs 10.4x less per output token ($0.15 vs $1.56 per million). Updated October 22, 2026; 38 benchmarks have a result for both.

Replace gpt-oss-20b Replace Qwen3.5-27B
gpt-oss-20bOpenAI
Coding
No data
Overall
38.5
Output $/M
$0.15
2
Qwen3.5-27BQwen
Coding
No data
Overall
No data
Output $/M
$1.56
36
vs boards won of 38 shared

gpt-oss-20b or Qwen3.5-27B: which to pick

Neither model has a coding score yet, so the two cannot be ranked on coding.

Pick gpt-oss-20b for output tokens 10.4x cheaper ($0.15 vs $1.56 per million) and work measured by Terminal-Bench Hard (Artificial Analysis run) or LMArena Text: coding, where it leads.

Model Agpt-oss-20bOpenAINot benchmarkedNo coding benchmarkNo cost per solved taskModel BQwen3.5-27BQwenNot benchmarked1 independent benchmarkNo cost per solved task
Shared results
38
gpt-oss-20b only
24
Qwen3.5-27B only
15
Like-for-like categories
7 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.

At a glance

Coding index
gpt-oss-20b not benchmarked, Qwen3.5-27B not benchmarked.
Widest category
Agentic work, 33.6 points apart on average over 1 shared benchmark.
Widest single gap
Long context reasoning (AA-LCR): gpt-oss-20b 34.7% against Qwen3.5-27B 77.7%, 43.0 points apart on a 0 to 100 scale.
Output price
gpt-oss-20b $0.15 against Qwen3.5-27B $1.56 per million output tokens, 10.4x apart.
Context window
gpt-oss-20b takes 131K tokens, Qwen3.5-27B 262K.

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.

Boards won, where both have a result
Categorygpt-oss-20bBarsQwen3.5-27BTies
Coding23
Intelligence01
Agentic work01
Reasoning05
Math02
Knowledge04
General020
All shared boards236
CodingLike-for-likeSix of these boards feed the Vibe Coding Index23
Coding benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
LMArena WebDevNot measured1358Only Qwen3.5-27B measured
LiveCodeBench (Vals AI)80.4%Not measuredOnly gpt-oss-20b measured
LiveCodeBench (Artificial Analysis run)77.7%Not measuredOnly gpt-oss-20b measured
SciCode38.9%Not measuredOnly gpt-oss-20b measured
Terminal-Bench Hard (Artificial Analysis run)10.6%32.6%Qwen3.5-27B
Terminal-Bench3.4%Not measuredOnly gpt-oss-20b measured
WeirdML40.9%39.5%gpt-oss-20b
ALE-Bench566.0349.4gpt-oss-20b
LMArena Text: coding13071427Qwen3.5-27B
LMArena Text: software and IT13111431Qwen3.5-27B
LMArena WebDev: ReactNot measured1346Only Qwen3.5-27B measured
LMArena WebDev: HTMLNot measured1386Only Qwen3.5-27B measured
Neither model has a result on the other 27 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
Intelligence benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
AA Intelligence Index10.022.9Qwen3.5-27B
Epoch Capabilities Index137.7Not measuredOnly gpt-oss-20b measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
τ²-Bench Telecom60.2%93.9%Qwen3.5-27B
Vending-Bench 2Not measured$202Only Qwen3.5-27B measured
BrowseComp-Plus50.6%Not measuredOnly gpt-oss-20b measured
Neither model has a result on the other 38 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index05
Reasoning benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
GPQA Diamond68.9%Not measuredOnly gpt-oss-20b measured
GPQA Diamond (Artificial Analysis run)68.8%85.8%Qwen3.5-27B
Humanity's Last Exam (Artificial Analysis run)11.0%23.9%Qwen3.5-27B
GPQA Diamond (Epoch AI run)60.8%Not measuredOnly gpt-oss-20b measured
LMArena Text: hard prompts12741415Qwen3.5-27B
LMArena Text: expert12581427Qwen3.5-27B
LMArena Text: hard prompts in English12921429Qwen3.5-27B
LMArena Vision: diagramsNot measured1249Only Qwen3.5-27B measured
LMArena Vision: homeworkNot measured1256Only Qwen3.5-27B measured
Kagi LLM Benchmark53.2%Not measuredOnly gpt-oss-20b measured
Neither model has a result on the other 12 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index02
Math benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
AIME86.0%Not measuredOnly gpt-oss-20b measured
MATH 500 (Vals AI)94.2%Not measuredOnly gpt-oss-20b measured
MGSM (Vals AI)89.0%Not measuredOnly gpt-oss-20b measured
AA Math Index89.3Not measuredOnly gpt-oss-20b measured
AIME 2025 (Artificial Analysis run)89.3%Not measuredOnly gpt-oss-20b measured
OTIS Mock AIME65.3%Not measuredOnly gpt-oss-20b measured
LMArena Text: math13171429Qwen3.5-27B
LMArena Text: mathematical work13051429Qwen3.5-27B
Neither model has a result on the other 5 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index04
Knowledge benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
MMLU Pro71.6%Not measuredOnly gpt-oss-20b measured
LegalBench (Vals AI)70.8%Not measuredOnly gpt-oss-20b measured
CaseLaw (Vals AI)43.8%Not measuredOnly gpt-oss-20b measured
CorpFin (Vals AI)53.1%Not measuredOnly gpt-oss-20b measured
TaxEval (Vals AI)63.7%Not measuredOnly gpt-oss-20b measured
MedQA (Vals AI)82.9%Not measuredOnly gpt-oss-20b measured
MMLU Pro (Artificial Analysis run)74.8%Not measuredOnly gpt-oss-20b measured
LMArena Text: science12961437Qwen3.5-27B
LMArena Text: medicine and healthcare13101425Qwen3.5-27B
LMArena Text: legal and government12801405Qwen3.5-27B
LMArena Text: business and finance12841399Qwen3.5-27B
Neither model has a result on the other 7 boards here
Web designDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
Web design benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
Design Arena: websites852Not measuredOnly gpt-oss-20b measured
Design Arena: data viz933Not measuredOnly gpt-oss-20b measured
Neither model has a result on the other 7 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index020
General benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
IFBench65.1%75.6%Qwen3.5-27B
Long context reasoning (AA-LCR)34.7%77.7%Qwen3.5-27B
DTBench68.0%82.4%Qwen3.5-27B
LMCA14.5%34.0%Qwen3.5-27B
LMArena Text12881409Qwen3.5-27B
LMArena Text: instruction following12361393Qwen3.5-27B
LMArena Text: creative writing12011362Qwen3.5-27B
LMArena VisionNot measured1241Only Qwen3.5-27B measured
LMArena Text: English13031425Qwen3.5-27B
LMArena Text: non-English12691390Qwen3.5-27B
LMArena Text: Chinese13151478Qwen3.5-27B
LMArena Text: German12551392Qwen3.5-27B
LMArena Text: Japanese12441346Qwen3.5-27B
LMArena Text: Korean12361359Qwen3.5-27B
LMArena Text: FrenchNot measured1410Only Qwen3.5-27B measured
LMArena Text: Spanish12671407Qwen3.5-27B
LMArena Text: Russian12781390Qwen3.5-27B
LMArena Text: Polish12521375Qwen3.5-27B
LMArena Text: multi-turn12681410Qwen3.5-27B
LMArena Text: longer queries12501413Qwen3.5-27B
LMArena Text: writing and language12381380Qwen3.5-27B
LMArena Text: entertainment and media12161363Qwen3.5-27B
LMArena Vision: EnglishNot measured1246Only Qwen3.5-27B measured
LMArena Vision: ChineseNot measured1301Only Qwen3.5-27B measured
LMArena Vision: reading textNot measured1246Only Qwen3.5-27B measured
LMArena Vision: humorNot measured1227Only Qwen3.5-27B measured
LMArena Vision: captioningNot measured1170Only Qwen3.5-27B measured
LMArena Vision: recognizing thingsNot measured1210Only Qwen3.5-27B measured
LMArena Vision: creative writingNot measured1224Only Qwen3.5-27B measured
Neither model has a result on the other 17 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for gpt-oss-20b and Qwen3.5-27B
Benchmarkgpt-oss-20bQwen3.5-27BLeader
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

gpt-oss-20b$0.0001Fits in one request
Qwen3.5-27B$0.0010Fits in one request

gpt-oss-20b costs less

Repository review

50K input + 3K output tokens

gpt-oss-20b$0.0019Fits in one request
Qwen3.5-27B$0.014Fits in one request

gpt-oss-20b costs less

Agent loop

200K input + 10K output tokens

gpt-oss-20b$0.0075Exceeds the context window
Qwen3.5-27B$0.055Fits in one request

gpt-oss-20b 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.

Specifications of gpt-oss-20b and Qwen3.5-27B
SpecificationOpenAI gpt-oss-20bQwen3.5-27B
MakerOpenAIQwen
WeightsOpen weightsOpen weights
ReleasedAugust 5, 2025February 25, 2026
Context window131K262K
Input $/Mtok$0.03$0.195
Output $/Mtok$0.15$1.56
Coding indexNot benchmarkedNot benchmarked
Independent measurements behind it01
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is gpt-oss-20b better than Qwen3.5-27B for coding?

Neither model has a coding score yet, so the two cannot be ranked on coding. Pick gpt-oss-20b for output tokens 10.4x cheaper ($0.15 vs $1.56 per million) and work measured by Terminal-Bench Hard (Artificial Analysis run) or LMArena Text: coding, where it leads.

Which is cheaper, gpt-oss-20b or Qwen3.5-27B?

gpt-oss-20b costs $0.03 per million input tokens and $0.15 per million output tokens; Qwen3.5-27B costs $0.195 and $1.56. Cost per solved task is known for neither of them.

Which has the bigger context window, gpt-oss-20b or Qwen3.5-27B?

Qwen3.5-27B, with 262K tokens against 131K.

How many benchmarks is the gpt-oss-20b vs Qwen3.5-27B comparison based on?

38 benchmarks have a result for both models as of October 22, 2026. gpt-oss-20b's coding index rests on 0 independent benchmarks and Qwen3.5-27B's on 1. Where only one model has a result, the page says so instead of naming a winner.

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