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GPT-5.1 vs Qwen3.5-Flash

Qwen3.5-Flash leads GPT-5.1 on coding, 41.1 to 40.4 on the Vibe Coding Index, and Qwen3.5-Flash costs 38.5x less per output token ($0.26 vs $10.00 per million). Updated October 22, 2026; 53 benchmarks have a result for both.

Replace GPT-5.1 Replace Qwen3.5-Flash
GPT-5.1OpenAI
Coding
40.4
Overall
55.0
Output $/M
$10.00
51
Qwen3.5-FlashQwen
Coding
41.1
Overall
50.1
Output $/M
$0.26
2
vs boards won of 53 shared

GPT-5.1 or Qwen3.5-Flash: which to pick

GPT-5.1 and Qwen3.5-Flash are level for coding, 40.4 against 41.1 on the Vibe Coding Index, so price and context decide.

Pick GPT-5.1 for work measured by LMArena WebDev or LiveCodeBench (Vals AI), where it leads. Pick Qwen3.5-Flash for output tokens 38.5x cheaper ($0.26 vs $10.00 per million) and a lower cost per solved task ($0.40 against $1.02).

Model AGPT-5.1OpenAI40.4/1003 independent benchmarks$1.02 per solved taskModel BQwen3.5-FlashQwen41.1/1002 independent benchmarks$0.40 per solved task
Shared results
53
GPT-5.1 only
48
Qwen3.5-Flash only
2
Like-for-like categories
6 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-5.1 40.4 from 3 benchmarks, Qwen3.5-Flash 41.1 from 2 benchmarks.
Widest category
Coding, 10.8 points apart on average over 7 shared benchmarks.
Widest single gap
Chess puzzles: GPT-5.1 42.0% against Qwen3.5-Flash 14.0%, 28.0 points apart on a 0 to 100 scale.
Output price
GPT-5.1 $10.00 against Qwen3.5-Flash $0.26 per million output tokens, 38.5x apart.
Context window
GPT-5.1 takes 400K 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.

Boards won, where both have a result
CategoryGPT-5.1BarsQwen3.5-FlashTies
Coding70
Intelligence10
Reasoning71
Math40
Knowledge111
General210
All shared boards512
CodingLike-for-likeSix of these boards feed the Vibe Coding Index70
Coding benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
SWE-bench Verified66.0%Not measuredOnly GPT-5.1 measured
LMArena WebDev13961244GPT-5.1
AA Coding Index49.4Not measuredOnly GPT-5.1 measured
LiveCodeBench (Vals AI)86.5%83.3%GPT-5.1
SWE-bench Verified (Vals AI)69.8%64.4%GPT-5.1
Vibe Code Bench (Vals AI)24.6%Not measuredOnly GPT-5.1 measured
LiveCodeBench (Artificial Analysis run)86.8%Not measuredOnly GPT-5.1 measured
Terminal-Bench Hard (Artificial Analysis run)45.5%Not measuredOnly GPT-5.1 measured
Terminal-Bench47.6%Not measuredOnly GPT-5.1 measured
GSO-Bench13.7%Not measuredOnly GPT-5.1 measured
WeirdML60.8%Not measuredOnly GPT-5.1 measured
ALE-BenchNot measured265.9Only Qwen3.5-Flash measured
LMArena Text: coding14531412GPT-5.1
LMArena Text: software and IT14541416GPT-5.1
LMArena WebDev: React13071229GPT-5.1
LMArena WebDev: HTML14051291GPT-5.1
LMArena WebDev: from an image1421Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 22 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
Intelligence benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
AA Intelligence Index24.7Not measuredOnly GPT-5.1 measured
Epoch Capabilities Index149.8143.5GPT-5.1
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index3 boards, none shared
Agentic work benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
τ²-Bench Telecom81.9%Not measuredOnly GPT-5.1 measured
DeepResearch Bench42.8%Not measuredOnly GPT-5.1 measured
Vending-Bench 2$1,473Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 38 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index71
Reasoning benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
GPQA Diamond86.6%82.8%GPT-5.1
MMMU Pro (Vals AI)83.2%81.9%GPT-5.1
GPQA Diamond (Artificial Analysis run)87.3%Not measuredOnly GPT-5.1 measured
Humanity's Last Exam (Artificial Analysis run)28.5%Not measuredOnly GPT-5.1 measured
GPQA Diamond (Epoch AI run)87.6%82.3%GPT-5.1
ARC-AGI72.8%Not measuredOnly GPT-5.1 measured
ARC-AGI-217.6%Not measuredOnly GPT-5.1 measured
SimpleBench53.2%Not measuredOnly GPT-5.1 measured
Chess puzzles42.0%14.0%GPT-5.1
Mystery game puzzles19.0%20.0%Qwen3.5-Flash
VPCT58.7%Not measuredOnly GPT-5.1 measured
LMArena Text: hard prompts14571403GPT-5.1
LMArena Text: expert14701407GPT-5.1
LMArena Text: hard prompts in English14621409GPT-5.1
LMArena Vision: diagrams1264Not measuredOnly GPT-5.1 measured
LMArena Vision: homework1272Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 6 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index40
Math benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
AIME93.3%92.5%GPT-5.1
MGSM (Vals AI)93.0%Not measuredOnly GPT-5.1 measured
AA Math Index94.0Not measuredOnly GPT-5.1 measured
AIME 2025 (Artificial Analysis run)94.0%Not measuredOnly GPT-5.1 measured
OTIS Mock AIME88.6%84.4%GPT-5.1
FrontierMath, tiers 1 to 3Not measured18.2%Only Qwen3.5-Flash measured
LMArena Text: math14461407GPT-5.1
LMArena Text: mathematical work14491413GPT-5.1
Neither model has a result on the other 5 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index111
Knowledge benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
MMLU Pro86.4%84.1%GPT-5.1
LegalBench (Vals AI)85.7%84.3%GPT-5.1
CaseLaw (Vals AI)73.4%56.0%GPT-5.1
CorpFin (Vals AI)63.8%63.6%GPT-5.1
TaxEval (Vals AI)74.9%72.2%GPT-5.1
MortgageTax (Vals AI)61.4%67.4%Qwen3.5-Flash
MedQA (Vals AI)96.4%Not measuredOnly GPT-5.1 measured
MedCode (Vals AI)52.7%33.0%GPT-5.1
MMLU Pro (Artificial Analysis run)87.0%Not measuredOnly GPT-5.1 measured
SimpleQA Verified48.0%20.3%GPT-5.1
LMArena Text: science14591415GPT-5.1
LMArena Text: medicine and healthcare14561407GPT-5.1
LMArena Text: legal and government14591398GPT-5.1
LMArena Text: business and finance14311394GPT-5.1
FACTS Benchmark Suite45.0%Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 3 boards here
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
Web design benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
Design Arena: websites1187Not measuredOnly GPT-5.1 measured
Design Arena: UI components1164Not measuredOnly GPT-5.1 measured
Design Arena: game dev1178Not measuredOnly GPT-5.1 measured
Design Arena: data viz1205Not measuredOnly GPT-5.1 measured
Design Arena: 3D1060Not measuredOnly GPT-5.1 measured
Design Arena: all code categories1170Not measuredOnly GPT-5.1 measured
Design Arena: SVG1148Not measuredOnly GPT-5.1 measured
Design Arena: ASCII art1118Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index210
General benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
SAGE (Vals AI)43.2%42.5%GPT-5.1
MedScribe (Vals AI)88.1%70.6%GPT-5.1
IFBench72.9%Not measuredOnly GPT-5.1 measured
Long context reasoning (AA-LCR)80.0%Not measuredOnly GPT-5.1 measured
DTBench90.1%82.9%GPT-5.1
LMCA43.9%29.1%GPT-5.1
CL-bench23.7%Not measuredOnly GPT-5.1 measured
CL-bench Life17.3%Not measuredOnly GPT-5.1 measured
LMArena Text14431397GPT-5.1
LMArena Text: instruction following14431374GPT-5.1
LMArena Text: creative writing14271343GPT-5.1
LMArena Vision1250Not measuredOnly GPT-5.1 measured
LMArena Text: English14511404GPT-5.1
LMArena Text: non-English14311385GPT-5.1
LMArena Text: Chinese14951445GPT-5.1
LMArena Text: German14381390GPT-5.1
LMArena Text: Japanese14531369GPT-5.1
LMArena Text: Korean14011344GPT-5.1
LMArena Text: French14501413GPT-5.1
LMArena Text: Spanish14331400GPT-5.1
LMArena Text: Russian14351380GPT-5.1
LMArena Text: Polish14401376GPT-5.1
LMArena Text: multi-turn14501393GPT-5.1
LMArena Text: longer queries14481392GPT-5.1
LMArena Text: writing and language14281369GPT-5.1
LMArena Text: entertainment and media14151347GPT-5.1
LMArena Vision: English1252Not measuredOnly GPT-5.1 measured
LMArena Vision: Chinese1270Not measuredOnly GPT-5.1 measured
LMArena Vision: reading text1255Not measuredOnly GPT-5.1 measured
LMArena Vision: humor1263Not measuredOnly GPT-5.1 measured
LMArena Vision: captioning1252Not measuredOnly GPT-5.1 measured
LMArena Vision: recognizing things1232Not measuredOnly GPT-5.1 measured
LMArena Vision: creative writing1266Not measuredOnly GPT-5.1 measured
LMArena Document1403Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 12 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-5.1 and Qwen3.5-Flash
BenchmarkGPT-5.1Qwen3.5-FlashLeader
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-5.1$0.0063Fits in one request
Qwen3.5-Flash$0.0002Fits in one request

Qwen3.5-Flash costs less

Repository review

50K input + 3K output tokens

GPT-5.1$0.092Fits in one request
Qwen3.5-Flash$0.0040Fits in one request

Qwen3.5-Flash costs less

Agent loop

200K input + 10K output tokens

GPT-5.1$0.350Fits in one request
Qwen3.5-Flash$0.016Fits in one request

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.

Specifications of GPT-5.1 and Qwen3.5-Flash
SpecificationOpenAI GPT-5.1Qwen3.5-Flash
MakerOpenAIQwen
WeightsNo public weights listedNo public weights listed
ReleasedNovember 13, 2025February 25, 2026
Context window400K1M
Input $/Mtok$1.25$0.065
Output $/Mtok$10.00$0.26
Coding index40.441.1
Independent measurements behind it32
Cost per solved task$1.02$0.40
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.1 better than Qwen3.5-Flash for coding?

GPT-5.1 and Qwen3.5-Flash are level for coding, 40.4 against 41.1 on the Vibe Coding Index, so price and context decide. Pick GPT-5.1 for work measured by LMArena WebDev or LiveCodeBench (Vals AI), where it leads. Pick Qwen3.5-Flash for output tokens 38.5x cheaper ($0.26 vs $10.00 per million) and a lower cost per solved task ($0.40 against $1.02).

Which is cheaper, GPT-5.1 or Qwen3.5-Flash?

GPT-5.1 costs $1.25 per million input tokens and $10.00 per million output tokens; Qwen3.5-Flash costs $0.065 and $0.26. Per solved SWE-bench Verified task, GPT-5.1 costs $1.02 and Qwen3.5-Flash $0.40.

Which has the bigger context window, GPT-5.1 or Qwen3.5-Flash?

Qwen3.5-Flash, with 1M tokens against 400K.

How many benchmarks is the GPT-5.1 vs Qwen3.5-Flash comparison based on?

53 benchmarks have a result for both models as of October 22, 2026. GPT-5.1's coding index rests on 3 independent benchmarks and Qwen3.5-Flash's on 2. Where only one model has a result, the page says so instead of naming a winner.

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<iframe src="https://llmbenchmark.ai/embed/compare/gpt-5-1-vs-qwen3-5-flash-02-23" title="GPT-5.1 vs Qwen3.5-Flash, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/gpt-5-1-vs-qwen3-5-flash-02-23">LLMBenchmark.ai, GPT-5.1 vs Qwen3.5-Flash</a></p>