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Claude Fable 5 vs Claude Sonnet 4.5

Claude Fable 5 leads Claude Sonnet 4.5 on coding, 79.3 to 39.5 on the Vibe Coding Index, and Claude Sonnet 4.5 costs 3.3x less per output token ($15.00 vs $50.00 per million). Updated October 22, 2026; 79 benchmarks have a result for both.

Replace Claude Fable 5 Replace Claude Sonnet 4.5
Claude Fable 5Anthropic
Coding
79.3
Overall
79.0
Output $/M
$50.00
79
Claude Sonnet 4.5Anthropic
Coding
39.5
Overall
49.5
Output $/M
$15.00
0
vs boards won of 79 shared

Claude Fable 5 or Claude Sonnet 4.5: which to pick

Pick Claude Fable 5 for coding: it scores 79.3 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5.

Pick Claude Sonnet 4.5 for output tokens 3.3x cheaper ($15.00 vs $50.00 per million) and a lower cost per solved task ($1.16 against $2.16).

Model AClaude Fable 5Anthropic79.3/1006 independent benchmarks$2.16 per solved taskModel BClaude Sonnet 4.5Anthropic39.5/1003 independent benchmarks$1.16 per solved task
Shared results
79
Claude Fable 5 only
48
Claude Sonnet 4.5 only
16
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 Sonnet 4.5 39.5 from 3 benchmarks.
Widest category
Math, 44.9 points apart on average over 6 shared benchmarks.
Widest single gap
FrontierMath, tier 4: Claude Fable 5 90.2% against Claude Sonnet 4.5 2.4%, 87.8 points apart on a 0 to 100 scale.
Output price
Claude Fable 5 $50.00 against Claude Sonnet 4.5 $15.00 per million output tokens, 3.3x 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 Sonnet 4.5Ties
Coding110
Intelligence20
Agentic work60
Reasoning130
Math60
Knowledge110
Web design80
General220
All shared boards790
CodingLike-for-likeSix of these boards feed the Vibe Coding Index110
Coding benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
SWE-bench VerifiedNot measured74.8%Only Claude Sonnet 4.5 measured
SWE-bench MultilingualNot measured67.0%Only Claude Sonnet 4.5 measured
LiveBench coding98.3%Not measuredOnly Claude Fable 5 measured
LMArena WebDev16241394Claude Fable 5
AA Coding Index76.552.1Claude Fable 5
LiveCodeBench (Vals AI)89.8%73.0%Claude Fable 5
SWE-bench Verified (Vals AI)95.0%70.0%Claude Fable 5
Terminal-Bench 4 (Vals AI)41.4%Not measuredOnly Claude Fable 5 measured
Vibe Code Bench (Vals AI)90.3%22.6%Claude Fable 5
Code migration (Vals AI)55.1%Not measuredOnly Claude Fable 5 measured
ProgramBench (Vals AI)2.0%Not measuredOnly Claude Fable 5 measured
Terminal-Bench 2.1 (Vals AI)80.5%Not measuredOnly Claude Fable 5 measured
SciCode61.0%Not measuredOnly Claude Fable 5 measured
Terminal-Bench Hard (Artificial Analysis run)62.9%Not measuredOnly Claude Fable 5 measured
Terminal-BenchNot measured46.5%Only Claude Sonnet 4.5 measured
FrontierCode53.5%Not measuredOnly Claude Fable 5 measured
FrontierSWE47.0%Not measuredOnly Claude Fable 5 measured
GSO-Bench78.4%14.7%Claude Fable 5
WeirdML91.9%47.7%Claude Fable 5
MirrorCode63.9%Not measuredOnly Claude Fable 5 measured
CybenchNot measured60.0%Only Claude Sonnet 4.5 measured
ALE-Bench2041.3Not measuredOnly Claude Fable 5 measured
LMArena Text: coding15181488Claude Fable 5
LMArena Text: software and IT15131473Claude Fable 5
LMArena WebDev: React16311386Claude Fable 5
LMArena WebDev: HTML16511399Claude Fable 5
LMArena WebDev: from an image1623Not measuredOnly Claude Fable 5 measured
Neither model has a result on the other 12 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
AA Intelligence Index49.620.7Claude Fable 5
Epoch Capabilities Index163.4146.7Claude Fable 5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index60
Agentic work benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
AA Agentic Index50.715.8Claude Fable 5
Design Arena: agents building web apps12611060Claude Fable 5
Design Arena: agents building full-stack apps12801050Claude Fable 5
Design Arena: agents building mobile apps12641137Claude Fable 5
Design Arena: agents building Android apps1284Not 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 slides1227Not measuredOnly Claude Fable 5 measured
Design Arena: PowerPoint slides1270Not measuredOnly Claude Fable 5 measured
LiveBench research86.9%Not measuredOnly Claude Fable 5 measured
LiveBench browser92.0%Not measuredOnly Claude Fable 5 measured
LiveBench long agentic53.2%Not measuredOnly Claude Fable 5 measured
Finance Agent (Vals AI)56.3%Not measuredOnly Claude Fable 5 measured
Tax Agent Bench (Vals AI)38.3%Not measuredOnly Claude Fable 5 measured
Legal Research Bench (Vals AI)49.5%Not measuredOnly Claude Fable 5 measured
Excel Modeling Benchmark (Vals AI)73.7%Not measuredOnly Claude Fable 5 measured
Terminal-Bench-Science (Vals AI)15.7%Not measuredOnly Claude Fable 5 measured
τ²-Bench Telecom98.5%Not measuredOnly Claude Fable 5 measured
APEX-Agents63.6%Not measuredOnly Claude Fable 5 measured
METR time horizonsNot measured67.4%Only Claude Sonnet 4.5 measured
Remote Labor Index16.1%2.1%Claude Fable 5
GDPvalNot measured42.5%Only Claude Sonnet 4.5 measured
DeepResearch BenchNot measured52.6%Only Claude Sonnet 4.5 measured
PostTrainBench41.8%Not measuredOnly Claude Fable 5 measured
OSWorldNot measured62.9%Only Claude Sonnet 4.5 measured
Vending-Bench 2$5,680$3,839Claude Fable 5
LMArena Search1229Not measuredOnly Claude Fable 5 measured
Berkeley Function Calling Leaderboard (BFCL)Not measured73.2%Only Claude Sonnet 4.5 measured
Neither model has a result on the other 13 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index130
Reasoning benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
GPQA Diamond93.2%81.6%Claude Fable 5
LiveBench reasoning89.7%Not measuredOnly Claude Fable 5 measured
MMMU Pro (Vals AI)89.3%79.3%Claude Fable 5
GPQA Diamond (Artificial Analysis run)92.6%Not measuredOnly Claude Fable 5 measured
Humanity's Last Exam (Artificial Analysis run)55.5%Not measuredOnly Claude Fable 5 measured
GPQA Diamond (Epoch AI run)85.9%82.3%Claude Fable 5
ARC-AGI98.5%63.7%Claude Fable 5
ARC-AGI-289.2%13.6%Claude Fable 5
SimpleBench81.9%54.3%Claude Fable 5
Chess puzzles47.0%10.0%Claude Fable 5
Mystery game puzzles52.0%17.0%Claude Fable 5
EBR-bench39.5%2.4%Claude Fable 5
VPCTNot measured39.8%Only Claude Sonnet 4.5 measured
LMArena Text: hard prompts15071462Claude Fable 5
LMArena Text: expert15341483Claude Fable 5
LMArena Text: hard prompts in English15091471Claude Fable 5
LMArena Vision: diagrams1357Not measuredOnly Claude Fable 5 measured
LMArena Vision: homework1361Not measuredOnly Claude Fable 5 measured
Kagi LLM Benchmark91.4%57.9%Claude Fable 5
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
AIMENot measured88.2%Only Claude Sonnet 4.5 measured
MGSM (Vals AI)Not measured94.3%Only Claude Sonnet 4.5 measured
OTIS Mock AIME100.0%77.8%Claude Fable 5
FrontierMath, tiers 1 to 387.0%23.9%Claude Fable 5
FrontierMath, tier 490.2%2.4%Claude Fable 5
ProofBench95.0%19.0%Claude Fable 5
MATH level 5Not measured97.7%Only Claude Sonnet 4.5 measured
LMArena Text: math15161449Claude Fable 5
LMArena Text: mathematical work15151462Claude Fable 5
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index110
Knowledge benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
MMLU Pro91.5%87.4%Claude Fable 5
LegalBench (Vals AI)88.6%84.1%Claude Fable 5
CaseLaw (Vals AI)Not measured62.2%Only Claude Sonnet 4.5 measured
CorpFin (Vals AI)71.8%62.0%Claude Fable 5
TaxEval (Vals AI)76.9%73.3%Claude Fable 5
MortgageTax (Vals AI)68.9%64.0%Claude Fable 5
MedQA (Vals AI)Not measured94.7%Only Claude Sonnet 4.5 measured
MedCode (Vals AI)56.1%44.1%Claude Fable 5
SimpleQA Verified70.7%30.7%Claude Fable 5
LMArena Text: science15061448Claude Fable 5
LMArena Text: medicine and healthcare14801444Claude Fable 5
LMArena Text: legal and government14981451Claude Fable 5
LMArena Text: business and finance14801440Claude Fable 5
FACTS Benchmark SuiteNot measured40.6%Only Claude Sonnet 4.5 measured
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index80
Web design benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
Design Arena: websites12951189Claude Fable 5
Design Arena: UI components13161170Claude Fable 5
Design Arena: game dev13351166Claude Fable 5
Design Arena: data viz13041167Claude Fable 5
Design Arena: 3D13181157Claude Fable 5
Design Arena: all code categories13101182Claude Fable 5
Design Arena: SVG13021115Claude Fable 5
Design Arena: ASCII art13291205Claude Fable 5
LiveBench design84.7%Not measuredOnly Claude Fable 5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index220
General benchmarks for Claude Fable 5 and Claude Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
LiveBench data analysis80.5%Not measuredOnly Claude Fable 5 measured
Public Benefits Bench (Vals AI)70.4%Not measuredOnly Claude Fable 5 measured
SAGE (Vals AI)51.9%36.1%Claude Fable 5
MedScribe (Vals AI)88.5%84.5%Claude Fable 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%Not measuredOnly Claude Fable 5 measured
DTBench98.4%83.2%Claude Fable 5
LMCA61.2%38.8%Claude Fable 5
Surface Evolver Bench95.0%Not measuredOnly Claude Fable 5 measured
Furniture assembly35.8%Not measuredOnly Claude Fable 5 measured
LMArena Text14911438Claude Fable 5
LMArena Text: instruction following15021459Claude Fable 5
LMArena Text: creative writing14941442Claude Fable 5
LMArena Vision1325Not measuredOnly Claude Fable 5 measured
LMArena Text: English14981450Claude Fable 5
LMArena Text: non-English14821425Claude Fable 5
LMArena Text: Chinese15431460Claude Fable 5
LMArena Text: German14861427Claude Fable 5
LMArena Text: Japanese15041390Claude Fable 5
LMArena Text: Korean14871402Claude Fable 5
LMArena Text: French15051459Claude Fable 5
LMArena Text: Spanish14981458Claude Fable 5
LMArena Text: Russian15031437Claude Fable 5
LMArena Text: Polish14941423Claude Fable 5
LMArena Text: multi-turn15041465Claude Fable 5
LMArena Text: longer queries15101475Claude Fable 5
LMArena Text: writing and language15011442Claude Fable 5
LMArena Text: entertainment and media14821428Claude Fable 5
LMArena Vision: English1323Not measuredOnly Claude Fable 5 measured
LMArena Vision: Chinese1373Not measuredOnly Claude Fable 5 measured
LMArena Vision: reading text1337Not measuredOnly Claude Fable 5 measured
LMArena Vision: humor1341Not measuredOnly Claude Fable 5 measured
LMArena Vision: creative writing1338Not measuredOnly Claude Fable 5 measured
LMArena Document14961450Claude Fable 5
Neither model has a result on the other 11 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 Sonnet 4.5
BenchmarkClaude Fable 5Claude Sonnet 4.5Leader
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 Sonnet 4.5$0.011Fits in one request

Claude Sonnet 4.5 costs less

Repository review

50K input + 3K output tokens

Claude Fable 5$0.650Fits in one request
Claude Sonnet 4.5$0.195Fits in one request

Claude Sonnet 4.5 costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5$2.50Fits in one request
Claude Sonnet 4.5$0.750Fits in one request

Claude Sonnet 4.5 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 Sonnet 4.5
SpecificationAnthropic Claude Fable 5Anthropic Claude Sonnet 4.5
MakerAnthropicAnthropic
WeightsNo public weights listedNo public weights listed
ReleasedJune 9, 2026September 29, 2025
Context window1M1M
Input $/Mtok$10.00$3.00
Output $/Mtok$50.00$15.00
Coding index79.339.5
Independent measurements behind it63
Cost per solved task$2.16$1.16
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5 better than Claude Sonnet 4.5 for coding?

Pick Claude Fable 5 for coding: it scores 79.3 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5. Pick Claude Sonnet 4.5 for output tokens 3.3x cheaper ($15.00 vs $50.00 per million) and a lower cost per solved task ($1.16 against $2.16).

Which is cheaper, Claude Fable 5 or Claude Sonnet 4.5?

Claude Fable 5 costs $10.00 per million input tokens and $50.00 per million output tokens; Claude Sonnet 4.5 costs $3.00 and $15.00. Per solved SWE-bench Verified task, Claude Fable 5 costs $2.16 and Claude Sonnet 4.5 $1.16.

Which has the bigger context window, Claude Fable 5 or Claude Sonnet 4.5?

Neither: both take 1M tokens.

How many benchmarks is the Claude Fable 5 vs Claude Sonnet 4.5 comparison based on?

79 benchmarks have a result for both models as of October 22, 2026. Claude Fable 5's coding index rests on 6 independent benchmarks and Claude Sonnet 4.5's on 3. 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-sonnet-4-5">LLMBenchmark.ai, Claude Fable 5 vs Claude Sonnet 4.5</a></p>