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Claude Fable 5.1 vs DeepSeek V4.1 Flash

Claude Fable 5.1 leads DeepSeek V4.1 Flash on coding, 84.2 to 62.5 on the Vibe Coding Index, and DeepSeek V4.1 Flash costs 59.5x less per output token ($0.84 vs $50.00 per million). Updated October 22, 2026; 97 benchmarks have a result for both.

Replace Claude Fable 5.1 Replace DeepSeek V4.1 Flash
Claude Fable 5.1Anthropic
Coding
84.2
Overall
84.7
Output $/M
$50.00
93
DeepSeek V4.1 FlashDeepSeek
Coding
62.5
Overall
62.4
Output $/M
$0.84
3
vs boards won of 97 shared, 1 tied

Claude Fable 5.1 or DeepSeek V4.1 Flash: which to pick

Pick Claude Fable 5.1 for coding: it scores 84.2 on the Vibe Coding Index against 62.5 for DeepSeek V4.1 Flash.

Pick DeepSeek V4.1 Flash for output tokens 59.5x cheaper ($0.84 vs $50.00 per million) and a larger context window (1.05M against 1M tokens).

Model AClaude Fable 5.1Anthropic84.2/1005 independent benchmarksNo cost per solved taskModel BDeepSeek V4.1 FlashDeepSeek62.5/1005 independent benchmarksNo cost per solved task
Shared results
97
Claude Fable 5.1 only
27
DeepSeek V4.1 Flash only
4
Like-for-like categories
8 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 Fable 5.1 84.2 from 5 benchmarks, DeepSeek V4.1 Flash 62.5 from 5 benchmarks.
Widest category
Math, 24.9 points apart on average over 6 shared benchmarks.
Widest single gap
FrontierMath, tier 4: Claude Fable 5.1 87.8% against DeepSeek V4.1 Flash 26.8%, 61.0 points apart on a 0 to 100 scale.
Output price
Claude Fable 5.1 $50.00 against DeepSeek V4.1 Flash $0.84 per million output tokens, 59.5x apart.
Context window
Claude Fable 5.1 takes 1M tokens, DeepSeek V4.1 Flash 1.05M.

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 5.1BarsDeepSeek V4.1 FlashTies
Coding182
Intelligence20
Agentic work91
Reasoning1101 tie
Math60
Knowledge70
Web design90
General310
All shared boards9331 tie
CodingLike-for-likeSix of these boards feed the Vibe Coding Index182
Coding benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
LiveBench coding97.7%90.2%Claude Fable 5.1
LMArena WebDev17431618Claude Fable 5.1
AA Coding Index81.6Not measuredOnly Claude Fable 5.1 measured
LiveCodeBench (Vals AI)90.5%Not measuredOnly Claude Fable 5.1 measured
Terminal-Bench 4 (Vals AI)58.1%19.7%Claude Fable 5.1
Vibe Code Bench (Vals AI)90.3%84.7%Claude Fable 5.1
Code migration (Vals AI)54.6%45.6%Claude Fable 5.1
ProgramBench (Vals AI)7.0%0.5%Claude Fable 5.1
IOI (Vals AI)90.8%40.3%Claude Fable 5.1
Terminal-Bench 2.1 (Vals AI)85.0%74.5%Claude Fable 5.1
SWE-bench Multimodal (Vals AI)61.3%46.5%Claude Fable 5.1
Vibe Code Bench 1-100 (Vals AI)28.0%16.4%Claude Fable 5.1
SkillsBench (Vals AI)61.5%69.8%DeepSeek V4.1 Flash
CyberBench (Vals AI)70.4%73.7%DeepSeek V4.1 Flash
SciCode63.1%51.9%Claude Fable 5.1
FrontierCode50.9%43.9%Claude Fable 5.1
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-Bench2143.21092.3Claude Fable 5.1
LMArena Text: coding15321502Claude Fable 5.1
LMArena Text: software and IT15301496Claude Fable 5.1
LMArena WebDev: React17921628Claude Fable 5.1
LMArena WebDev: HTML16841612Claude Fable 5.1
LMArena WebDev: from an image17221606Claude Fable 5.1
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
AA Intelligence Index53.424.7Claude Fable 5.1
Epoch Capabilities Index166.5155.9Claude Fable 5.1
Agentic workLike-for-likePublic boards, shown as published, kept out of the index91
Agentic work benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
AA Agentic Index57.9Not measuredOnly Claude Fable 5.1 measured
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 slides1305Not measuredOnly Claude Fable 5.1 measured
Design Arena: spreadsheets1380Not measuredOnly Claude Fable 5.1 measured
LiveBench research82.0%86.8%DeepSeek V4.1 Flash
LiveBench browser100.0%84.0%Claude Fable 5.1
LiveBench long agentic80.8%40.1%Claude Fable 5.1
SREBench (Vals AI)22.9%0.8%Claude Fable 5.1
Finance Agent (Vals AI)58.9%53.5%Claude Fable 5.1
Tax Agent Bench (Vals AI)49.2%26.6%Claude Fable 5.1
Legal Research Bench (Vals AI)55.3%41.4%Claude Fable 5.1
Excel Modeling Benchmark (Vals AI)76.7%57.2%Claude Fable 5.1
BioMysteryBench (Vals AI)Not measured67.8%Only DeepSeek V4.1 Flash measured
Terminal-Bench-Science (Vals AI)40.0%0.0%Claude Fable 5.1
Vals Science IndexNot measured29.6%Only DeepSeek V4.1 Flash measured
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%39.5%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 index110
Reasoning benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
GPQA Diamond93.4%Not measuredOnly Claude Fable 5.1 measured
LiveBench reasoning91.7%86.7%Claude Fable 5.1
MysteryMechanism (Vals AI)47.8%21.2%Claude Fable 5.1
MMMU Pro (Vals AI)90.6%Not measuredOnly Claude Fable 5.1 measured
GPQA Diamond (Artificial Analysis run)93.7%Not measuredOnly Claude Fable 5.1 measured
Humanity's Last Exam (Artificial Analysis run)59.1%39.2%Claude Fable 5.1
GPQA Diamond (Epoch AI run)Not measured89.8%Only DeepSeek V4.1 Flash measured
ARC-AGI97.5%94.5%Claude Fable 5.1
ARC-AGI-290.0%72.9%Claude Fable 5.1
Chess puzzles48.0%48.0%Tie
Mystery game puzzles58.0%43.0%Claude Fable 5.1
EBR-bench57.1%Not measuredOnly Claude Fable 5.1 measured
LMArena Text: hard prompts15281483Claude Fable 5.1
LMArena Text: expert15441501Claude Fable 5.1
LMArena Text: hard prompts in English15221488Claude Fable 5.1
LMArena Vision: diagrams13431297Claude Fable 5.1
LMArena Vision: homework13451307Claude 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 index60
Math benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
OTIS Mock AIME100.0%98.3%Claude Fable 5.1
FrontierMath, tiers 1 to 390.2%67.4%Claude Fable 5.1
FrontierMath, tier 487.8%26.8%Claude Fable 5.1
ProofBench100.0%54.0%Claude Fable 5.1
LMArena Text: math15311478Claude Fable 5.1
LMArena Text: mathematical work15411485Claude 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 index70
Knowledge benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
MMLU Pro92.4%Not measuredOnly Claude Fable 5.1 measured
LegalBench (Vals AI)88.5%83.3%Claude Fable 5.1
TaxEval (Vals AI)76.0%Not measuredOnly Claude Fable 5.1 measured
MortgageTax (Vals AI)70.8%Not measuredOnly Claude Fable 5.1 measured
MedCode (Vals AI)53.5%41.2%Claude Fable 5.1
SimpleQA Verified70.8%42.9%Claude Fable 5.1
LMArena Text: science15321469Claude Fable 5.1
LMArena Text: medicine and healthcare15311484Claude Fable 5.1
LMArena Text: legal and government15141443Claude Fable 5.1
LMArena Text: business and finance14931461Claude Fable 5.1
Neither model has a result on the other 8 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index90
Web design benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
Design Arena: websites13121308Claude Fable 5.1
Design Arena: UI components13361312Claude Fable 5.1
Design Arena: game dev13811330Claude Fable 5.1
Design Arena: data viz13441291Claude Fable 5.1
Design Arena: 3D13921355Claude Fable 5.1
Design Arena: all code categories13351320Claude Fable 5.1
Design Arena: SVG13001245Claude Fable 5.1
Design Arena: ASCII art13231265Claude Fable 5.1
LiveBench design83.4%79.2%Claude Fable 5.1
GeneralLike-for-likePublic boards, shown as published, kept out of the index310
General benchmarks for Claude Fable 5.1 and DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 FlashLeader
LiveBench data analysis80.3%79.3%Claude Fable 5.1
Public Benefits Bench (Vals AI)74.9%64.3%Claude Fable 5.1
SAGE (Vals AI)48.5%47.9%Claude Fable 5.1
MedScribe (Vals AI)91.3%85.5%Claude Fable 5.1
Long context reasoning (AA-LCR)85.3%84.0%Claude Fable 5.1
DTBench97.6%89.9%Claude Fable 5.1
LMCA65.5%47.0%Claude Fable 5.1
Surface Evolver BenchNot measured46.3%Only DeepSeek V4.1 Flash measured
Furniture assembly70.0%34.2%Claude Fable 5.1
LMArena Text15121464Claude Fable 5.1
LMArena Text: instruction following15181473Claude Fable 5.1
LMArena Text: creative writing15091437Claude Fable 5.1
LMArena Vision13191278Claude Fable 5.1
LMArena Text: English15061473Claude Fable 5.1
LMArena Text: non-English15081449Claude Fable 5.1
LMArena Text: Chinese15841501Claude Fable 5.1
LMArena Text: German14991470Claude Fable 5.1
LMArena Text: Japanese15621432Claude Fable 5.1
LMArena Text: Korean15171436Claude Fable 5.1
LMArena Text: French15231465Claude Fable 5.1
LMArena Text: Spanish15201459Claude Fable 5.1
LMArena Text: Russian15201467Claude Fable 5.1
LMArena Text: Polish15251457Claude Fable 5.1
LMArena Text: multi-turn14931461Claude Fable 5.1
LMArena Text: longer queries15241473Claude Fable 5.1
LMArena Text: writing and language15101450Claude Fable 5.1
LMArena Text: entertainment and media14971445Claude Fable 5.1
LMArena Vision: English13131288Claude Fable 5.1
LMArena Vision: Chinese13911327Claude Fable 5.1
LMArena Vision: reading text13271282Claude Fable 5.1
LMArena Vision: humor13181260Claude Fable 5.1
LMArena Vision: creative writing13301275Claude 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 DeepSeek V4.1 Flash
BenchmarkClaude Fable 5.1DeepSeek V4.1 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

Claude Fable 5.1$0.035Fits in one request
DeepSeek V4.1 Flash$0.0006Fits in one request

DeepSeek V4.1 Flash costs less

Repository review

50K input + 3K output tokens

Claude Fable 5.1$0.650Fits in one request
DeepSeek V4.1 Flash$0.014Fits in one request

DeepSeek V4.1 Flash costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5.1$2.50Fits in one request
DeepSeek V4.1 Flash$0.053Fits in one request

DeepSeek V4.1 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 Claude Fable 5.1 and DeepSeek V4.1 Flash
SpecificationAnthropic Claude Fable 5.1DeepSeek V4.1 Flash
MakerAnthropicDeepSeek
WeightsNo public weights listedOpen weights
ReleasedSeptember 1, 2026September 10, 2026
Context window1M1.05M
Input $/Mtok$10.00$0.2225
Output $/Mtok$50.00$0.84
Coding index84.262.5
Independent measurements behind it55
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5.1 better than DeepSeek V4.1 Flash for coding?

Pick Claude Fable 5.1 for coding: it scores 84.2 on the Vibe Coding Index against 62.5 for DeepSeek V4.1 Flash. Pick DeepSeek V4.1 Flash for output tokens 59.5x cheaper ($0.84 vs $50.00 per million) and a larger context window (1.05M against 1M tokens).

Which is cheaper, Claude Fable 5.1 or DeepSeek V4.1 Flash?

Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; DeepSeek V4.1 Flash costs $0.2225 and $0.84. Cost per solved task is known for neither of them.

Which has the bigger context window, Claude Fable 5.1 or DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash, with 1.05M tokens against 1M.

How many benchmarks is the Claude Fable 5.1 vs DeepSeek V4.1 Flash comparison based on?

97 benchmarks have a result for both models as of October 22, 2026. Claude Fable 5.1's coding index rests on 5 independent benchmarks and DeepSeek V4.1 Flash's on 5. Where only one model has a result, the page says so instead of naming a winner.

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