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Claude Sonnet 4.5 vs Qwen3.8 27B

Qwen3.8 27B leads Claude Sonnet 4.5 on coding, 74.2 to 39.5 on the Vibe Coding Index, and Qwen3.8 27B costs 5.9x less per output token ($2.55 vs $15.00 per million). Updated October 22, 2026; 52 benchmarks have a result for both.

Replace Claude Sonnet 4.5 Replace Qwen3.8 27B
Claude Sonnet 4.5Anthropic
Coding
39.5
Overall
49.5
Output $/M
$15.00
25
Qwen3.8 27BQwen
Coding
74.2
Overall
59.6
Output $/M
$2.55
27
vs boards won of 52 shared

Claude Sonnet 4.5 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 Claude Sonnet 4.5.

Pick Claude Sonnet 4.5 for a lower cost per solved task ($1.16 against $1.26) and work measured by LMArena Text: coding or LMArena Text: hard prompts, where it leads.

Model AClaude Sonnet 4.5Anthropic39.5/1003 independent benchmarks$1.16 per solved taskModel BQwen3.8 27BQwen74.2/1004 independent benchmarks$1.26 per solved task
Shared results
52
Claude Sonnet 4.5 only
43
Qwen3.8 27B only
33
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
Claude Sonnet 4.5 39.5 from 3 benchmarks, Qwen3.8 27B 74.2 from 4 benchmarks.
Widest category
Agentic work, 30.0 points apart on average over 1 shared benchmark.
Widest single gap
Vibe Code Bench (Vals AI): Claude Sonnet 4.5 22.6% against Qwen3.8 27B 64.8%, 42.2 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 4.5 $15.00 against Qwen3.8 27B $2.55 per million output tokens, 5.9x 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.

Boards won, where both have a result
CategoryClaude Sonnet 4.5BarsQwen3.8 27BTies
Coding18
Intelligence02
Agentic work01
Reasoning34
Math21
Knowledge72
General129
All shared boards2527
CodingLike-for-likeSix of these boards feed the Vibe Coding Index18
Coding benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
SWE-bench Verified74.8%Not measuredOnly Claude Sonnet 4.5 measured
SWE-bench Multilingual67.0%Not measuredOnly Claude Sonnet 4.5 measured
LiveBench codingNot measured86.8%Only Qwen3.8 27B measured
LMArena WebDev13941593Qwen3.8 27B
AA Coding Index52.168.1Qwen3.8 27B
LiveCodeBench (Vals AI)73.0%84.0%Qwen3.8 27B
SWE-bench Verified (Vals AI)70.0%86.0%Qwen3.8 27B
Vibe Code Bench (Vals AI)22.6%64.8%Qwen3.8 27B
Code migration (Vals AI)Not measured14.2%Only Qwen3.8 27B measured
ProgramBench (Vals AI)Not measured0.0%Only Qwen3.8 27B measured
IOI (Vals AI)Not measured39.1%Only Qwen3.8 27B measured
Terminal-Bench 2.1 (Vals AI)Not measured58.4%Only Qwen3.8 27B measured
SkillsBench (Vals AI)Not measured38.1%Only Qwen3.8 27B measured
CyberBench (Vals AI)Not measured67.8%Only Qwen3.8 27B measured
SciCodeNot measured46.6%Only Qwen3.8 27B measured
Terminal-Bench46.5%Not measuredOnly Claude Sonnet 4.5 measured
GSO-Bench14.7%Not measuredOnly Claude Sonnet 4.5 measured
WeirdML47.7%Not measuredOnly Claude Sonnet 4.5 measured
Cybench60.0%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: coding14881483Claude Sonnet 4.5
LMArena Text: software and IT14731478Qwen3.8 27B
LMArena WebDev: React13861602Qwen3.8 27B
LMArena WebDev: HTML13991570Qwen3.8 27B
LMArena WebDev: from an imageNot measured1577Only Qwen3.8 27B measured
Neither model has a result on the other 15 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
AA Intelligence Index20.733.7Qwen3.8 27B
Epoch Capabilities Index146.7151.7Qwen3.8 27B
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
AA Agentic Index15.845.8Qwen3.8 27B
Design Arena: agents building web apps1060Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: agents building full-stack apps1050Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: agents building mobile apps1137Not measuredOnly Claude Sonnet 4.5 measured
LiveBench researchNot measured59.4%Only Qwen3.8 27B measured
LiveBench browserNot measured32.0%Only Qwen3.8 27B measured
LiveBench long agenticNot measured27.9%Only Qwen3.8 27B measured
Finance Agent (Vals AI)Not measured48.5%Only Qwen3.8 27B measured
Tax Agent Bench (Vals AI)Not measured30.9%Only Qwen3.8 27B measured
Legal Research Bench (Vals AI)Not measured36.1%Only Qwen3.8 27B measured
Excel Modeling Benchmark (Vals AI)Not measured59.7%Only Qwen3.8 27B measured
Terminal-Bench-Science (Vals AI)Not measured0.0%Only Qwen3.8 27B measured
APEX-AgentsNot measured47.5%Only Qwen3.8 27B measured
METR time horizons67.4%Not measuredOnly Claude Sonnet 4.5 measured
Remote Labor Index2.1%Not measuredOnly Claude Sonnet 4.5 measured
GDPval42.5%Not measuredOnly Claude Sonnet 4.5 measured
DeepResearch Bench52.6%Not measuredOnly Claude Sonnet 4.5 measured
OSWorld62.9%Not measuredOnly Claude Sonnet 4.5 measured
Vending-Bench 2$3,839Not measuredOnly Claude Sonnet 4.5 measured
Berkeley Function Calling Leaderboard (BFCL)73.2%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 21 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index34
Reasoning benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
GPQA Diamond81.6%88.9%Qwen3.8 27B
LiveBench reasoningNot measured80.0%Only Qwen3.8 27B measured
MMMU Pro (Vals AI)79.3%83.9%Qwen3.8 27B
GPQA Diamond (Artificial Analysis run)Not measured90.5%Only Qwen3.8 27B measured
Humanity's Last Exam (Artificial Analysis run)Not measured33.9%Only Qwen3.8 27B measured
GPQA Diamond (Epoch AI run)82.3%Not measuredOnly Claude Sonnet 4.5 measured
ARC-AGI63.7%87.5%Qwen3.8 27B
ARC-AGI-213.6%42.4%Qwen3.8 27B
SimpleBench54.3%Not measuredOnly Claude Sonnet 4.5 measured
Chess puzzles10.0%Not measuredOnly Claude Sonnet 4.5 measured
Mystery game puzzles17.0%Not measuredOnly Claude Sonnet 4.5 measured
EBR-bench2.4%Not measuredOnly Claude Sonnet 4.5 measured
VPCT39.8%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: hard prompts14621459Claude Sonnet 4.5
LMArena Text: expert14831479Claude Sonnet 4.5
LMArena Text: hard prompts in English14711461Claude Sonnet 4.5
LMArena Vision: diagramsNot measured1285Only Qwen3.8 27B measured
LMArena Vision: homeworkNot measured1295Only Qwen3.8 27B measured
Kagi LLM Benchmark57.9%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index21
Math benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
AIME88.2%Not measuredOnly Claude Sonnet 4.5 measured
MGSM (Vals AI)94.3%Not measuredOnly Claude Sonnet 4.5 measured
OTIS Mock AIME77.8%Not measuredOnly Claude Sonnet 4.5 measured
FrontierMath, tiers 1 to 323.9%Not measuredOnly Claude Sonnet 4.5 measured
FrontierMath, tier 42.4%Not measuredOnly Claude Sonnet 4.5 measured
ProofBench19.0%16.0%Claude Sonnet 4.5
MATH level 597.7%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: math14491455Qwen3.8 27B
LMArena Text: mathematical work14621458Claude Sonnet 4.5
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index72
Knowledge benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
MMLU Pro87.4%84.3%Claude Sonnet 4.5
LegalBench (Vals AI)84.1%82.4%Claude Sonnet 4.5
CaseLaw (Vals AI)62.2%Not measuredOnly Claude Sonnet 4.5 measured
CorpFin (Vals AI)62.0%Not measuredOnly Claude Sonnet 4.5 measured
TaxEval (Vals AI)73.3%70.8%Claude Sonnet 4.5
MortgageTax (Vals AI)64.0%64.9%Qwen3.8 27B
MedQA (Vals AI)94.7%Not measuredOnly Claude Sonnet 4.5 measured
MedCode (Vals AI)44.1%28.7%Claude Sonnet 4.5
SimpleQA Verified30.7%Not measuredOnly Claude Sonnet 4.5 measured
LMArena Text: science14481467Qwen3.8 27B
LMArena Text: medicine and healthcare14441437Claude Sonnet 4.5
LMArena Text: legal and government14511447Claude Sonnet 4.5
LMArena Text: business and finance14401438Claude Sonnet 4.5
FACTS Benchmark Suite40.6%Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 4 boards here
Web designDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
Web design benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
Design Arena: websites1189Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: UI components1170Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: game dev1166Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: data viz1167Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: 3D1157Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: all code categories1182Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: SVG1115Not measuredOnly Claude Sonnet 4.5 measured
Design Arena: ASCII art1205Not measuredOnly Claude Sonnet 4.5 measured
LiveBench designNot measured75.9%Only Qwen3.8 27B measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index129
General benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 27BLeader
LiveBench data analysisNot measured76.6%Only Qwen3.8 27B measured
SAGE (Vals AI)36.1%52.4%Qwen3.8 27B
MedScribe (Vals AI)84.5%83.8%Claude Sonnet 4.5
Long context reasoning (AA-LCR)Not measured82.0%Only Qwen3.8 27B measured
DTBench83.2%88.0%Qwen3.8 27B
LMCA38.8%41.4%Qwen3.8 27B
Surface Evolver BenchNot measured45.0%Only Qwen3.8 27B measured
LMArena Text14381440Qwen3.8 27B
LMArena Text: instruction following14591436Claude Sonnet 4.5
LMArena Text: creative writing14421383Claude Sonnet 4.5
LMArena VisionNot measured1269Only Qwen3.8 27B measured
LMArena Text: English14501448Claude Sonnet 4.5
LMArena Text: non-English14251428Qwen3.8 27B
LMArena Text: Chinese14601501Qwen3.8 27B
LMArena Text: German14271443Qwen3.8 27B
LMArena Text: Japanese13901387Claude Sonnet 4.5
LMArena Text: Korean14021384Claude Sonnet 4.5
LMArena Text: French14591465Qwen3.8 27B
LMArena Text: Spanish14581449Claude Sonnet 4.5
LMArena Text: Russian14371415Claude Sonnet 4.5
LMArena Text: Polish14231439Qwen3.8 27B
LMArena Text: multi-turn14651440Claude Sonnet 4.5
LMArena Text: longer queries14751448Claude Sonnet 4.5
LMArena Text: writing and language14421405Claude Sonnet 4.5
LMArena Text: entertainment and media14281393Claude Sonnet 4.5
LMArena Vision: EnglishNot measured1267Only Qwen3.8 27B measured
LMArena Vision: ChineseNot measured1326Only Qwen3.8 27B measured
LMArena Vision: reading textNot measured1281Only Qwen3.8 27B measured
LMArena Vision: humorNot measured1235Only Qwen3.8 27B measured
LMArena Vision: creative writingNot measured1237Only Qwen3.8 27B measured
LMArena Document1450Not measuredOnly Claude Sonnet 4.5 measured
Neither model has a result on the other 15 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Sonnet 4.5 and Qwen3.8 27B
BenchmarkClaude Sonnet 4.5Qwen3.8 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

Claude Sonnet 4.5$0.011Fits in one request
Qwen3.8 27B$0.0017Fits in one request

Qwen3.8 27B costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 4.5$0.195Fits in one request
Qwen3.8 27B$0.029Fits in one request

Qwen3.8 27B costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 4.5$0.750Fits in one request
Qwen3.8 27B$0.111Fits in one request

Qwen3.8 27B 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 Claude Sonnet 4.5 and Qwen3.8 27B
SpecificationAnthropic Claude Sonnet 4.5Qwen3.8 27B
MakerAnthropicQwen
WeightsNo public weights listedOpen weights
ReleasedSeptember 29, 2025August 14, 2026
Context window1M1M
Input $/Mtok$3.00$0.425
Output $/Mtok$15.00$2.55
Coding index39.574.2
Independent measurements behind it34
Cost per solved task$1.16$1.26
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 4.5 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 Claude Sonnet 4.5. Pick Claude Sonnet 4.5 for a lower cost per solved task ($1.16 against $1.26) and work measured by LMArena Text: coding or LMArena Text: hard prompts, where it leads.

Which is cheaper, Claude Sonnet 4.5 or Qwen3.8 27B?

Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; Qwen3.8 27B costs $0.425 and $2.55. Per solved SWE-bench Verified task, Claude Sonnet 4.5 costs $1.16 and Qwen3.8 27B $1.26.

Which has the bigger context window, Claude Sonnet 4.5 or Qwen3.8 27B?

Neither: both take 1M tokens.

How many benchmarks is the Claude Sonnet 4.5 vs Qwen3.8 27B comparison based on?

52 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 4.5's coding index rests on 3 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.

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<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/claude-sonnet-4-5-vs-qwen3-8-27b">LLMBenchmark.ai, Claude Sonnet 4.5 vs Qwen3.8 27B</a></p>