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Claude Fable 5 vs Claude Opus 5.5

Claude Opus 5.5 leads Claude Fable 5 on coding, 88.8 to 79.3 on the Vibe Coding Index, and Claude Opus 5.5 costs 2.5x less per output token ($20.00 vs $50.00 per million). Updated October 21, 2026; 92 benchmarks have a result for both.

Replace Claude Fable 5 Replace Claude Opus 5.5
Claude Fable 5Anthropic
Coding
79.3
Overall
79.0
Output $/M
$50.00
15
Claude Opus 5.5Anthropic
Coding
88.8
Overall
87.1
Output $/M
$20.00
75
vs boards won of 92 shared, 2 tied

Claude Fable 5 or Claude Opus 5.5: which to pick

Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 79.3 for Claude Fable 5, though on 5 benchmarks against 6.

Pick Claude Fable 5 for work measured by LiveBench coding or Vibe Code Bench (Vals AI), where it leads.

Model AClaude Fable 5Anthropic79.3/1006 independent benchmarks$2.16 per solved taskModel BClaude Opus 5.5Anthropic88.8/1005 independent benchmarksNo cost per solved task
Shared results
92
Claude Fable 5 only
35
Claude Opus 5.5 only
17
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 79.3 from 6 benchmarks, Claude Opus 5.5 88.8 from 5 benchmarks.
Widest category
Agentic work, 10.2 points apart on average over 14 shared benchmarks.
Widest single gap
Furniture assembly: Claude Fable 5 35.8% against Claude Opus 5.5 83.3%, 47.5 points apart on a 0 to 100 scale.
Output price
Claude Fable 5 $50.00 against Claude Opus 5.5 $20.00 per million output tokens, 2.5x 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 5BarsClaude Opus 5.5Ties
Coding215
Intelligence02
Agentic work311
Reasoning1111 tie
Math051 tie
Knowledge15
Web design08
General818
All shared boards15752 ties
CodingLike-for-likeSix of these boards feed the Vibe Coding Index215
Coding benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
LiveBench coding98.3%96.3%Claude Fable 5
LMArena WebDev16241807Claude Opus 5.5
AA Coding Index76.5Not measuredOnly Claude Fable 5 measured
LiveCodeBench (Vals AI)89.8%Not measuredOnly Claude Fable 5 measured
SWE-bench Verified (Vals AI)95.0%Not measuredOnly Claude Fable 5 measured
Terminal-Bench 4 (Vals AI)41.4%65.2%Claude Opus 5.5
Vibe Code Bench (Vals AI)90.3%90.3%Claude Fable 5
Code migration (Vals AI)55.1%66.7%Claude Opus 5.5
ProgramBench (Vals AI)2.0%18.5%Claude Opus 5.5
IOI (Vals AI)Not measured95.1%Only Claude Opus 5.5 measured
Terminal-Bench 2.1 (Vals AI)80.5%87.6%Claude Opus 5.5
SWE-bench Multimodal (Vals AI)Not measured70.2%Only Claude Opus 5.5 measured
Vibe Code Bench 1-100 (Vals AI)Not measured30.4%Only Claude Opus 5.5 measured
CyberBench (Vals AI)Not measured74.6%Only Claude Opus 5.5 measured
SciCode61.0%66.9%Claude Opus 5.5
Terminal-Bench Hard (Artificial Analysis run)62.9%Not measuredOnly Claude Fable 5 measured
FrontierCode53.5%54.6%Claude Opus 5.5
FrontierSWE47.0%62.3%Claude Opus 5.5
GSO-Bench78.4%Not measuredOnly Claude Fable 5 measured
WeirdML91.9%Not measuredOnly Claude Fable 5 measured
MirrorCode63.9%77.4%Claude Opus 5.5
ALE-Bench2041.32147.4Claude Opus 5.5
LMArena Text: coding15181545Claude Opus 5.5
LMArena Text: software and IT15131538Claude Opus 5.5
LMArena WebDev: React16311855Claude Opus 5.5
LMArena WebDev: HTML16511753Claude Opus 5.5
LMArena WebDev: from an image16231753Claude Opus 5.5
SciCodeNot measured18.5%Only Claude Opus 5.5 measured
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
AA Intelligence Index49.657.6Claude Opus 5.5
Epoch Capabilities Index163.4168.8Claude Opus 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index311
Agentic work benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
AA Agentic Index50.7Not measuredOnly Claude Fable 5 measured
Design Arena: agents building web apps12611317Claude Opus 5.5
Design Arena: agents building full-stack apps1280Not measuredOnly Claude Fable 5 measured
Design Arena: agents building mobile apps12641310Claude Opus 5.5
Design Arena: agents building Android apps1283Not measuredOnly Claude Fable 5 measured
Design Arena: agents building Godot games1292Not measuredOnly Claude Fable 5 measured
Design Arena: agents building games1285Not measuredOnly Claude Fable 5 measured
Design Arena: HTML slides1277Not measuredOnly Claude Fable 5 measured
Design Arena: PowerPoint slides1295Not measuredOnly Claude Fable 5 measured
Design Arena: spreadsheetsNot measured1352Only Claude Opus 5.5 measured
LiveBench research86.9%85.0%Claude Fable 5
LiveBench browser92.0%80.0%Claude Fable 5
LiveBench long agentic53.2%85.0%Claude Opus 5.5
SREBench (Vals AI)Not measured33.6%Only Claude Opus 5.5 measured
Finance Agent (Vals AI)56.3%58.6%Claude Opus 5.5
Tax Agent Bench (Vals AI)38.3%45.6%Claude Opus 5.5
Legal Research Bench (Vals AI)49.5%50.5%Claude Opus 5.5
Harvey's Legal Agent Benchmark (Vals AI)Not measured9.2%Only Claude Opus 5.5 measured
Excel Modeling Benchmark (Vals AI)73.7%75.9%Claude Opus 5.5
BioMysteryBench (Vals AI)Not measured79.3%Only Claude Opus 5.5 measured
Terminal-Bench-Science (Vals AI)15.7%47.1%Claude Opus 5.5
Vals Science IndexNot measured58.7%Only Claude Opus 5.5 measured
Time Horizon Index (Vals AI)Not measured91.3%Only Claude Opus 5.5 measured
CUA-bench (Vals AI)Not measured14.0%Only Claude Opus 5.5 measured
Robo-bench (Vals AI)Not measured14.6%Only Claude Opus 5.5 measured
τ²-Bench Telecom98.5%Not measuredOnly Claude Fable 5 measured
APEX-Agents63.6%73.5%Claude Opus 5.5
Remote Labor Index16.1%21.3%Claude Opus 5.5
PostTrainBench41.8%Not measuredOnly Claude Fable 5 measured
SpireClimbNot measured3.3%Only Claude Opus 5.5 measured
Vending-Bench 2$5,680$9,235Claude Opus 5.5
LMArena Search12291213Claude Fable 5
Neither model has a result on the other 9 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index111
Reasoning benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
GPQA Diamond93.2%Not measuredOnly Claude Fable 5 measured
LiveBench reasoning89.7%92.2%Claude Opus 5.5
MysteryMechanism (Vals AI)Not measured49.5%Only Claude Opus 5.5 measured
MMMU Pro (Vals AI)89.3%Not measuredOnly Claude Fable 5 measured
GPQA Diamond (Artificial Analysis run)92.6%Not measuredOnly Claude Fable 5 measured
Humanity's Last Exam (Artificial Analysis run)55.5%61.4%Claude Opus 5.5
GPQA Diamond (Epoch AI run)85.9%90.6%Claude Opus 5.5
ARC-AGI98.5%98.5%Tie
ARC-AGI-289.2%93.3%Claude Opus 5.5
SimpleBench81.9%Not measuredOnly Claude Fable 5 measured
Chess puzzles47.0%67.0%Claude Opus 5.5
Mystery game puzzles52.0%71.0%Claude Opus 5.5
EBR-bench39.5%71.4%Claude Opus 5.5
LMArena Text: hard prompts15071536Claude Opus 5.5
LMArena Text: expert15341549Claude Opus 5.5
LMArena Text: hard prompts in English15091535Claude Opus 5.5
LMArena Vision: diagrams13571345Claude Fable 5
LMArena Vision: homework13611362Claude Opus 5.5
Kagi LLM Benchmark91.4%Not measuredOnly Claude Fable 5 measured
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index05
Math benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
OTIS Mock AIME100.0%100.0%Tie
FrontierMath, tiers 1 to 387.0%91.2%Claude Opus 5.5
FrontierMath, tier 490.2%95.0%Claude Opus 5.5
ProofBench95.0%100.0%Claude Opus 5.5
LMArena Text: math15161518Claude Opus 5.5
LMArena Text: mathematical work15151516Claude Opus 5.5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index15
Knowledge benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
MMLU Pro91.5%Not measuredOnly Claude Fable 5 measured
LegalBench (Vals AI)88.6%Not measuredOnly Claude Fable 5 measured
CorpFin (Vals AI)71.8%Not measuredOnly Claude Fable 5 measured
TaxEval (Vals AI)76.9%Not measuredOnly Claude Fable 5 measured
MortgageTax (Vals AI)68.9%Not measuredOnly Claude Fable 5 measured
MedCode (Vals AI)56.1%49.8%Claude Fable 5
SimpleQA Verified70.7%72.2%Claude Opus 5.5
LMArena Text: science15061524Claude Opus 5.5
LMArena Text: medicine and healthcare14801509Claude Opus 5.5
LMArena Text: legal and government14981518Claude Opus 5.5
LMArena Text: business and finance14801494Claude Opus 5.5
FACTS Benchmark SuiteNot measured65.3%Only Claude Opus 5.5 measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index08
Web design benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
Design Arena: websites12961336Claude Opus 5.5
Design Arena: UI components13191392Claude Opus 5.5
Design Arena: game dev13351458Claude Opus 5.5
Design Arena: data viz13041397Claude Opus 5.5
Design Arena: 3D13191477Claude Opus 5.5
Design Arena: all code categories13101390Claude Opus 5.5
Design Arena: SVG13021333Claude Opus 5.5
Design Arena: ASCII art1329Not measuredOnly Claude Fable 5 measured
LiveBench design84.7%86.9%Claude Opus 5.5
GeneralLike-for-likePublic boards, shown as published, kept out of the index818
General benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
Vals IndexNot measured70.2%Only Claude Opus 5.5 measured
LiveBench data analysis80.5%80.3%Claude Fable 5
Public Benefits Bench (Vals AI)70.4%70.6%Claude Opus 5.5
SAGE (Vals AI)51.9%45.8%Claude Fable 5
MedScribe (Vals AI)88.5%91.4%Claude Opus 5.5
Vals Multimodal Index74.2%Not measuredOnly Claude Fable 5 measured
IFBench63.5%Not measuredOnly Claude Fable 5 measured
Long context reasoning (AA-LCR)82.3%84.7%Claude Opus 5.5
DTBench98.4%98.9%Claude Opus 5.5
LMCA61.2%68.2%Claude Opus 5.5
Surface Evolver Bench95.0%Not measuredOnly Claude Fable 5 measured
Furniture assembly35.8%83.3%Claude Opus 5.5
LMArena Text14911516Claude Opus 5.5
LMArena Text: instruction following15021537Claude Opus 5.5
LMArena Text: creative writing14941535Claude Opus 5.5
LMArena Vision13251321Claude Fable 5
LMArena Text: English14981519Claude Opus 5.5
LMArena Text: non-English14821507Claude Opus 5.5
LMArena Text: Chinese15431582Claude Opus 5.5
LMArena Text: German1486Not measuredOnly Claude Fable 5 measured
LMArena Text: Japanese15041534Claude Opus 5.5
LMArena Text: Korean1487Not measuredOnly Claude Fable 5 measured
LMArena Text: French15051493Claude Fable 5
LMArena Text: Spanish14981508Claude Opus 5.5
LMArena Text: Russian15031517Claude Opus 5.5
LMArena Text: Polish1494Not measuredOnly Claude Fable 5 measured
LMArena Text: multi-turn15041501Claude Fable 5
LMArena Text: longer queries15101532Claude Opus 5.5
LMArena Text: writing and language15011532Claude Opus 5.5
LMArena Text: entertainment and media14821515Claude Opus 5.5
LMArena Vision: English13231317Claude Fable 5
LMArena Vision: Chinese1373Not measuredOnly Claude Fable 5 measured
LMArena Vision: reading text13371326Claude Fable 5
LMArena Vision: humor1341Not measuredOnly Claude Fable 5 measured
LMArena Vision: creative writing13381320Claude Fable 5
LMArena Document1496Not measuredOnly Claude Fable 5 measured
Neither model has a result on the other 10 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Fable 5 and Claude Opus 5.5
BenchmarkClaude Fable 5Claude Opus 5.5Leader
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$0.035Fits in one request
Claude Opus 5.5$0.014Fits in one request

Claude Opus 5.5 costs less

Repository review

50K input + 3K output tokens

Claude Fable 5$0.650Fits in one request
Claude Opus 5.5$0.260Fits in one request

Claude Opus 5.5 costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5$2.50Fits in one request
Claude Opus 5.5$1.00Fits in one request

Claude Opus 5.5 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 and Claude Opus 5.5
SpecificationAnthropic Claude Fable 5Anthropic Claude Opus 5.5
MakerAnthropicAnthropic
WeightsNo public weights listedNo public weights listed
ReleasedJune 9, 2026September 22, 2026
Context window1M1M
Input $/Mtok$10.00$4.00
Output $/Mtok$50.00$20.00
Coding index79.388.8
Independent measurements behind it65
Cost per solved task$2.16Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5 better than Claude Opus 5.5 for coding?

Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 79.3 for Claude Fable 5, though on 5 benchmarks against 6. Pick Claude Fable 5 for work measured by LiveBench coding or Vibe Code Bench (Vals AI), where it leads.

Which is cheaper, Claude Fable 5 or Claude Opus 5.5?

Claude Fable 5 costs $10.00 per million input tokens and $50.00 per million output tokens; Claude Opus 5.5 costs $4.00 and $20.00. Cost per solved task is known for Claude Fable 5 only.

Which has the bigger context window, Claude Fable 5 or Claude Opus 5.5?

Neither: both take 1M tokens.

How many benchmarks is the Claude Fable 5 vs Claude Opus 5.5 comparison based on?

92 benchmarks have a result for both models as of October 21, 2026. Claude Fable 5's coding index rests on 6 independent benchmarks and Claude Opus 5.5's on 5. 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-fable-5-vs-claude-opus-5-5">LLMBenchmark.ai, Claude Fable 5 vs Claude Opus 5.5</a></p>