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Claude Fable 5.1 vs Qwen3.8 27B

Updated October 21, 2026. 83 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Fable 5.1 Replace Qwen3.8 27B
Claude Fable 5.1Anthropic
Coding
89.1
Overall
53.4
Output $/M
$50.00
82
Qwen3.8 27BQwen
Coding
73.6
Overall
33.7
Output $/M
$1.35
1
vs boards won of 83 shared

Decision reading

Pick Claude Fable 5.1 for coding: it scores 89.1 on the Vibe Coding Index against 73.6 for Qwen3.8 27B.

Pick Qwen3.8 27B when output tokens cost 37.0x less, or when the benchmark that matters is SAGE (Vals AI), where it leads.

Model AClaude Fable 5.1Anthropic89.1/1002 independent benchmarksNo cost per solved taskModel BQwen3.8 27BQwen73.6/1002 independent benchmarks$1.26 per solved task
Shared results
83
Claude Fable 5.1 only
41
Qwen3.8 27B only
2
Like-for-like categories
8 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.

At a glance

Coding index
Claude Fable 5.1 89.1 from 2 benchmarks, Qwen3.8 27B 73.6 from 2 benchmarks.
Widest category
Math, 36.8 points apart on average over 3 shared benchmarks.
Widest single gap
ProofBench: Claude Fable 5.1 100.0% against Qwen3.8 27B 16.0%, 84.0 points apart on a 0 to 100 scale.
Output price
Claude Fable 5.1 $50.00 against Qwen3.8 27B $1.35 per million output tokens, 37.0x 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 Fable 5.1BarsQwen3.8 27BTies
Coding170
Intelligence20
Agentic work100
Reasoning120
Math30
Knowledge90
Web design10
General281
All shared boards821
CodingLike-for-likeFour of these boards feed the Vibe Coding Index170
Coding benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
LiveBench coding97.7%86.8%Claude Fable 5.1
LMArena WebDev17431593Claude Fable 5.1
AA Coding Index81.668.1Claude Fable 5.1
LiveCodeBench (Vals AI)90.5%84.0%Claude Fable 5.1
SWE-bench Verified (Vals AI)Not measured86.0%Only Qwen3.8 27B measured
Terminal-Bench 4 (Vals AI)58.1%Not measuredOnly Claude Fable 5.1 measured
Vibe Code Bench (Vals AI)90.3%64.8%Claude Fable 5.1
Code migration (Vals AI)54.6%14.2%Claude Fable 5.1
ProgramBench (Vals AI)7.0%0.0%Claude Fable 5.1
IOI (Vals AI)90.8%39.1%Claude Fable 5.1
Terminal-Bench 2.1 (Vals AI)85.0%58.4%Claude Fable 5.1
SWE-bench Multimodal (Vals AI)61.3%Not measuredOnly Claude Fable 5.1 measured
Vibe Code Bench 1-100 (Vals AI)28.0%Not measuredOnly Claude Fable 5.1 measured
SkillsBench (Vals AI)61.5%38.1%Claude Fable 5.1
CyberBench (Vals AI)70.4%67.8%Claude Fable 5.1
SciCode63.1%46.6%Claude Fable 5.1
FrontierCode50.9%Not measuredOnly Claude Fable 5.1 measured
FrontierSWE56.3%Not measuredOnly Claude Fable 5.1 measured
GSO-Bench88.2%Not measuredOnly Claude Fable 5.1 measured
WeirdML92.9%Not measuredOnly Claude Fable 5.1 measured
MirrorCode73.3%Not measuredOnly Claude Fable 5.1 measured
ALE-Bench2143.2Not measuredOnly Claude Fable 5.1 measured
LMArena Text: coding15321483Claude Fable 5.1
LMArena Text: software and IT15301478Claude Fable 5.1
LMArena WebDev: React17921602Claude Fable 5.1
LMArena WebDev: HTML16841570Claude Fable 5.1
LMArena WebDev: from an image17221577Claude Fable 5.1
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
AA Intelligence Index53.433.7Claude Fable 5.1
Epoch Capabilities Index166.5151.7Claude Fable 5.1
Agentic workLike-for-likePublic boards, shown as published, kept out of the index100
Agentic work benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
AA Agentic Index57.945.8Claude Fable 5.1
Design Arena: agents building web apps1318Not measuredOnly Claude Fable 5.1 measured
Design Arena: agents building full-stack apps1326Not measuredOnly Claude Fable 5.1 measured
Design Arena: agents building mobile apps1267Not measuredOnly Claude Fable 5.1 measured
Design Arena: agents building Godot games1327Not measuredOnly Claude Fable 5.1 measured
Design Arena: PowerPoint slides1328Not measuredOnly Claude Fable 5.1 measured
Design Arena: spreadsheets1374Not measuredOnly Claude Fable 5.1 measured
LiveBench research82.0%59.4%Claude Fable 5.1
LiveBench browser100.0%32.0%Claude Fable 5.1
LiveBench long agentic80.8%27.9%Claude Fable 5.1
SREBench (Vals AI)22.9%Not measuredOnly Claude Fable 5.1 measured
Finance Agent (Vals AI)58.9%48.5%Claude Fable 5.1
Tax Agent Bench (Vals AI)49.2%30.9%Claude Fable 5.1
Legal Research Bench (Vals AI)55.3%36.1%Claude Fable 5.1
Excel Modeling Benchmark (Vals AI)76.7%59.7%Claude Fable 5.1
Terminal-Bench-Science (Vals AI)40.0%0.0%Claude Fable 5.1
Time Horizon Index (Vals AI)63.3%Not measuredOnly Claude Fable 5.1 measured
CUA-bench (Vals AI)13.2%Not measuredOnly Claude Fable 5.1 measured
Robo-bench (Vals AI)5.8%Not measuredOnly Claude Fable 5.1 measured
APEX-Agents68.6%47.5%Claude Fable 5.1
Remote Labor Index17.9%Not measuredOnly Claude Fable 5.1 measured
SpireClimb2.0%Not measuredOnly Claude Fable 5.1 measured
Vending-Bench 2$5,422Not measuredOnly Claude Fable 5.1 measured
LMArena Search1246Not measuredOnly Claude Fable 5.1 measured
Neither model has a result on the other 15 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index120
Reasoning benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
GPQA Diamond93.4%88.9%Claude Fable 5.1
LiveBench reasoning91.7%80.0%Claude Fable 5.1
MysteryMechanism (Vals AI)47.8%Not measuredOnly Claude Fable 5.1 measured
MMMU Pro (Vals AI)90.6%83.9%Claude Fable 5.1
GPQA Diamond (Artificial Analysis run)93.7%90.5%Claude Fable 5.1
Humanity's Last Exam (Artificial Analysis run)59.1%33.9%Claude Fable 5.1
ARC-AGI97.5%87.5%Claude Fable 5.1
ARC-AGI-290.0%42.4%Claude Fable 5.1
Chess puzzles48.0%Not measuredOnly Claude Fable 5.1 measured
Mystery game puzzles58.0%Not measuredOnly Claude Fable 5.1 measured
EBR-bench57.1%Not measuredOnly Claude Fable 5.1 measured
LMArena Text: hard prompts15281459Claude Fable 5.1
LMArena Text: expert15441479Claude Fable 5.1
LMArena Text: hard prompts in English15221461Claude Fable 5.1
LMArena Vision: diagrams13431285Claude Fable 5.1
LMArena Vision: homework13451295Claude Fable 5.1
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index30
Math benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
OTIS Mock AIME100.0%Not measuredOnly Claude Fable 5.1 measured
FrontierMath, tiers 1 to 390.2%Not measuredOnly Claude Fable 5.1 measured
FrontierMath, tier 487.8%Not measuredOnly Claude Fable 5.1 measured
ProofBench100.0%16.0%Claude Fable 5.1
LMArena Text: math15311455Claude Fable 5.1
LMArena Text: mathematical work15411458Claude Fable 5.1
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index90
Knowledge benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
MMLU Pro92.4%84.3%Claude Fable 5.1
LegalBench (Vals AI)88.5%82.4%Claude Fable 5.1
TaxEval (Vals AI)76.0%70.8%Claude Fable 5.1
MortgageTax (Vals AI)70.8%64.9%Claude Fable 5.1
MedCode (Vals AI)53.5%28.7%Claude Fable 5.1
SimpleQA Verified70.8%Not measuredOnly Claude Fable 5.1 measured
LMArena Text: science15321467Claude Fable 5.1
LMArena Text: medicine and healthcare15311437Claude Fable 5.1
LMArena Text: legal and government15141447Claude Fable 5.1
LMArena Text: business and finance14931438Claude Fable 5.1
Neither model has a result on the other 7 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index10
Web design benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
Design Arena: websites1313Not measuredOnly Claude Fable 5.1 measured
Design Arena: UI components1338Not measuredOnly Claude Fable 5.1 measured
Design Arena: game dev1382Not measuredOnly Claude Fable 5.1 measured
Design Arena: data viz1344Not measuredOnly Claude Fable 5.1 measured
Design Arena: 3D1393Not measuredOnly Claude Fable 5.1 measured
Design Arena: all code categories1336Not measuredOnly Claude Fable 5.1 measured
Design Arena: SVG1301Not measuredOnly Claude Fable 5.1 measured
Design Arena: ASCII art1324Not measuredOnly Claude Fable 5.1 measured
LiveBench design83.4%75.9%Claude Fable 5.1
GeneralLike-for-likePublic boards, shown as published, kept out of the index281
General benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 27BLeader
LiveBench data analysis80.3%76.6%Claude Fable 5.1
Public Benefits Bench (Vals AI)74.9%Not measuredOnly Claude Fable 5.1 measured
SAGE (Vals AI)48.5%52.4%Qwen3.8 27B
MedScribe (Vals AI)91.3%83.8%Claude Fable 5.1
Long context reasoning (AA-LCR)85.3%82.0%Claude Fable 5.1
DTBench97.6%88.0%Claude Fable 5.1
LMCA65.5%41.4%Claude Fable 5.1
Surface Evolver BenchNot measured45.0%Only Qwen3.8 27B measured
Furniture assembly70.0%Not measuredOnly Claude Fable 5.1 measured
LMArena Text15121440Claude Fable 5.1
LMArena Text: instruction following15181436Claude Fable 5.1
LMArena Text: creative writing15091383Claude Fable 5.1
LMArena Vision13191269Claude Fable 5.1
LMArena Text: English15061448Claude Fable 5.1
LMArena Text: non-English15081428Claude Fable 5.1
LMArena Text: Chinese15841501Claude Fable 5.1
LMArena Text: German14991443Claude Fable 5.1
LMArena Text: Japanese15621387Claude Fable 5.1
LMArena Text: Korean15171384Claude Fable 5.1
LMArena Text: French15231465Claude Fable 5.1
LMArena Text: Spanish15201449Claude Fable 5.1
LMArena Text: Russian15201415Claude Fable 5.1
LMArena Text: Polish15251439Claude Fable 5.1
LMArena Text: multi-turn14931440Claude Fable 5.1
LMArena Text: longer queries15241448Claude Fable 5.1
LMArena Text: writing and language15101405Claude Fable 5.1
LMArena Text: entertainment and media14971393Claude Fable 5.1
LMArena Vision: English13131267Claude Fable 5.1
LMArena Vision: Chinese13911326Claude Fable 5.1
LMArena Vision: reading text13271281Claude Fable 5.1
LMArena Vision: humor13181235Claude Fable 5.1
LMArena Vision: creative writing13301237Claude Fable 5.1
Neither model has a result on the other 14 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Fable 5.1 and Qwen3.8 27B
BenchmarkClaude Fable 5.1Qwen3.8 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 Fable 5.1$0.035Fits in one request
Qwen3.8 27B$0.0007Fits in one request

Qwen3.8 27B costs less

Repository review

50K input + 3K output tokens

Claude Fable 5.1$0.650Fits in one request
Qwen3.8 27B$0.0060Fits in one request

Qwen3.8 27B costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5.1$2.50Fits in one request
Qwen3.8 27B$0.021Fits 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 Fable 5.1 and Qwen3.8 27B
SpecificationAnthropic Claude Fable 5.1Qwen3.8 27B
MakerAnthropicQwen
WeightsNo public weights listedOpen weights
ReleasedSeptember 1, 2026August 14, 2026
Context window1M1M
Input $/Mtok$10.00$0.04
Output $/Mtok$50.00$1.35
Coding index89.173.6
Independent measurements behind it22
Cost per solved taskNot computable$1.26
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5.1 better than Qwen3.8 27B for coding?

Pick Claude Fable 5.1 for coding: it scores 89.1 on the Vibe Coding Index against 73.6 for Qwen3.8 27B. Pick Qwen3.8 27B when output tokens cost 37.0x less, or when the benchmark that matters is SAGE (Vals AI), where it leads.

Which is cheaper, Claude Fable 5.1 or Qwen3.8 27B?

Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; Qwen3.8 27B costs $0.04 and $1.35. Cost per solved task is known for Qwen3.8 27B only.

Which has the bigger context window, Claude Fable 5.1 or Qwen3.8 27B?

Neither: both take 1M tokens.

How many benchmarks is the Claude Fable 5.1 vs Qwen3.8 27B comparison based on?

83 benchmarks have a result for both models as of October 21, 2026. Claude Fable 5.1's coding index rests on 2 independent benchmarks and Qwen3.8 27B's on 2. Where only one model has a result, the page says so instead of naming a winner.

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