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Claude Fable 5 vs GPT-5.4

Claude Fable 5 leads GPT-5.4 on coding, 79.3 to 64.4 on the Vibe Coding Index, and GPT-5.4 costs 3.3x less per output token ($15.00 vs $50.00 per million). Updated October 21, 2026; 100 benchmarks have a result for both.

Replace Claude Fable 5 Replace GPT-5.4
Claude Fable 5Anthropic
Coding
79.3
Overall
79.0
Output $/M
$50.00
95
GPT-5.4OpenAI
Coding
64.4
Overall
69.6
Output $/M
$15.00
5
vs boards won of 100 shared

Claude Fable 5 or GPT-5.4: which to pick

Pick Claude Fable 5 for coding: it scores 79.3 on the Vibe Coding Index against 64.4 for GPT-5.4.

Pick GPT-5.4 for output tokens 3.3x cheaper ($15.00 vs $50.00 per million) and a lower cost per solved task ($1.02 against $2.16).

Model AClaude Fable 5Anthropic79.3/1006 independent benchmarks$2.16 per solved taskModel BGPT-5.4OpenAI64.4/1003 independent benchmarks$1.02 per solved task
Shared results
100
Claude Fable 5 only
27
GPT-5.4 only
10
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, GPT-5.4 64.4 from 3 benchmarks.
Widest category
Agentic work, 20.0 points apart on average over 9 shared benchmarks.
Widest single gap
MirrorCode: Claude Fable 5 63.9% against GPT-5.4 15.6%, 48.3 points apart on a 0 to 100 scale.
Output price
Claude Fable 5 $50.00 against GPT-5.4 $15.00 per million output tokens, 3.3x apart.
Context window
Claude Fable 5 takes 1M tokens, GPT-5.4 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 5BarsGPT-5.4Ties
Coding170
Intelligence20
Agentic work81
Reasoning142
Math60
Knowledge110
Web design80
General292
All shared boards955
CodingLike-for-likeSix of these boards feed the Vibe Coding Index170
Coding benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
LiveBench coding98.3%Not measuredOnly Claude Fable 5 measured
LMArena WebDev16241464Claude Fable 5
AA Coding Index76.571.1Claude Fable 5
LiveCodeBench (Vals AI)89.8%84.1%Claude Fable 5
SWE-bench Verified (Vals AI)95.0%78.2%Claude Fable 5
Terminal-Bench 4 (Vals AI)41.4%Not measuredOnly Claude Fable 5 measured
Vibe Code Bench (Vals AI)90.3%67.4%Claude Fable 5
Code migration (Vals AI)55.1%35.0%Claude Fable 5
ProgramBench (Vals AI)2.0%0.5%Claude Fable 5
Terminal-Bench 2.1 (Vals AI)80.5%Not measuredOnly Claude Fable 5 measured
SkillsBench (Vals AI)Not measured51.7%Only GPT-5.4 measured
SciCode61.0%Not measuredOnly Claude Fable 5 measured
Terminal-Bench Hard (Artificial Analysis run)62.9%57.6%Claude Fable 5
Terminal-BenchNot measured81.8%Only GPT-5.4 measured
FrontierCode53.5%Not measuredOnly Claude Fable 5 measured
FrontierSWE47.0%Not measuredOnly Claude Fable 5 measured
GSO-Bench78.4%31.4%Claude Fable 5
WeirdML91.9%77.7%Claude Fable 5
MirrorCode63.9%15.6%Claude Fable 5
ALE-Bench2041.31607.0Claude Fable 5
LMArena Text: coding15181496Claude Fable 5
LMArena Text: software and IT15131491Claude Fable 5
LMArena WebDev: React16311454Claude Fable 5
LMArena WebDev: HTML16511478Claude Fable 5
LMArena WebDev: from an image16231436Claude Fable 5
Neither model has a result on the other 14 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
AA Intelligence Index49.639.0Claude Fable 5
Epoch Capabilities Index163.4157.3Claude Fable 5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index81
Agentic work benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
AA Agentic Index50.7Not measuredOnly Claude Fable 5 measured
Design Arena: agents building web apps12611059Claude Fable 5
Design Arena: agents building full-stack apps12801017Claude Fable 5
Design Arena: agents building mobile apps12641087Claude Fable 5
Design Arena: agents building Android apps12831030Claude Fable 5
Design Arena: agents building Godot games12921135Claude Fable 5
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
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%87.1%Claude Fable 5
APEX-Agents63.6%52.4%Claude Fable 5
METR time horizonsNot measured74.3%Only GPT-5.4 measured
Remote Labor Index16.1%Not measuredOnly Claude Fable 5 measured
DeepResearch BenchNot measured35.1%Only GPT-5.4 measured
PostTrainBench41.8%19.0%Claude Fable 5
Vending-Bench 2$5,680$6,144GPT-5.4
LMArena Search1229Not measuredOnly Claude Fable 5 measured
Neither model has a result on the other 16 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index142
Reasoning benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
GPQA Diamond93.2%91.7%Claude Fable 5
LiveBench reasoning89.7%Not measuredOnly Claude Fable 5 measured
MMMU Pro (Vals AI)89.3%87.5%Claude Fable 5
GPQA Diamond (Artificial Analysis run)92.6%92.0%Claude Fable 5
Humanity's Last Exam (Artificial Analysis run)55.5%43.7%Claude Fable 5
GPQA Diamond (Epoch AI run)85.9%93.3%GPT-5.4
ARC-AGI98.5%93.7%Claude Fable 5
ARC-AGI-289.2%74.0%Claude Fable 5
SimpleBench81.9%Not measuredOnly Claude Fable 5 measured
Chess puzzles47.0%48.0%GPT-5.4
Mystery game puzzles52.0%37.0%Claude Fable 5
EBR-bench39.5%25.4%Claude Fable 5
LMArena Text: hard prompts15071485Claude Fable 5
LMArena Text: expert15341507Claude Fable 5
LMArena Text: hard prompts in English15091479Claude Fable 5
LMArena Vision: diagrams13571327Claude Fable 5
LMArena Vision: homework13611336Claude Fable 5
Kagi LLM Benchmark91.4%63.8%Claude Fable 5
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
AIMENot measured96.7%Only GPT-5.4 measured
OTIS Mock AIME100.0%97.8%Claude Fable 5
FrontierMath, tiers 1 to 387.0%78.6%Claude Fable 5
FrontierMath, tier 490.2%49.0%Claude Fable 5
ProofBench95.0%56.0%Claude Fable 5
LMArena Text: math15161488Claude Fable 5
LMArena Text: mathematical work15151497Claude Fable 5
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index110
Knowledge benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
MMLU Pro91.5%87.5%Claude Fable 5
LegalBench (Vals AI)88.6%86.0%Claude Fable 5
CaseLaw (Vals AI)Not measured63.8%Only GPT-5.4 measured
CorpFin (Vals AI)71.8%65.3%Claude Fable 5
TaxEval (Vals AI)76.9%74.0%Claude Fable 5
MortgageTax (Vals AI)68.9%68.3%Claude Fable 5
MedQA (Vals AI)Not measured96.1%Only GPT-5.4 measured
MedCode (Vals AI)56.1%41.3%Claude Fable 5
SimpleQA Verified70.7%45.1%Claude Fable 5
LMArena Text: science15061479Claude Fable 5
LMArena Text: medicine and healthcare14801458Claude Fable 5
LMArena Text: legal and government14981486Claude Fable 5
LMArena Text: business and finance14801474Claude Fable 5
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index80
Web design benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
Design Arena: websites12961199Claude Fable 5
Design Arena: UI components13191215Claude Fable 5
Design Arena: game dev13351195Claude Fable 5
Design Arena: data viz13041196Claude Fable 5
Design Arena: 3D13191066Claude Fable 5
Design Arena: all code categories13101180Claude Fable 5
Design Arena: SVG13021142Claude Fable 5
Design Arena: ASCII art13291188Claude Fable 5
LiveBench design84.7%Not measuredOnly Claude Fable 5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index292
General benchmarks for Claude Fable 5 and GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
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%43.3%Claude Fable 5
MedScribe (Vals AI)88.5%77.5%Claude Fable 5
Vals Multimodal Index74.2%Not measuredOnly Claude Fable 5 measured
IFBench63.5%73.9%GPT-5.4
Long context reasoning (AA-LCR)82.3%82.0%Claude Fable 5
DTBench98.4%94.4%Claude Fable 5
LMCA61.2%52.0%Claude Fable 5
CL-benchNot measured27.9%Only GPT-5.4 measured
Surface Evolver Bench95.0%Not measuredOnly Claude Fable 5 measured
Furniture assembly35.8%37.5%GPT-5.4
CL-bench LifeNot measured21.7%Only GPT-5.4 measured
LMArena Text14911469Claude Fable 5
LMArena Text: instruction following15021469Claude Fable 5
LMArena Text: creative writing14941439Claude Fable 5
LMArena Vision13251303Claude Fable 5
LMArena Text: English14981467Claude Fable 5
LMArena Text: non-English14821465Claude Fable 5
LMArena Text: Chinese15431520Claude Fable 5
LMArena Text: German14861472Claude Fable 5
LMArena Text: Japanese15041485Claude Fable 5
LMArena Text: Korean14871449Claude Fable 5
LMArena Text: French15051493Claude Fable 5
LMArena Text: Spanish14981452Claude Fable 5
LMArena Text: Russian15031480Claude Fable 5
LMArena Text: Polish14941472Claude Fable 5
LMArena Text: multi-turn15041482Claude Fable 5
LMArena Text: longer queries15101473Claude Fable 5
LMArena Text: writing and language15011458Claude Fable 5
LMArena Text: entertainment and media14821438Claude Fable 5
LMArena Vision: English13231301Claude Fable 5
LMArena Vision: Chinese13731354Claude Fable 5
LMArena Vision: reading text13371312Claude Fable 5
LMArena Vision: humor13411284Claude Fable 5
LMArena Vision: recognizing thingsNot measured1251Only GPT-5.4 measured
LMArena Vision: creative writing13381283Claude Fable 5
LMArena Document14961471Claude Fable 5
Neither model has a result on the other 8 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 GPT-5.4
BenchmarkClaude Fable 5GPT-5.4Leader
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
GPT-5.4$0.010Fits in one request

GPT-5.4 costs less

Repository review

50K input + 3K output tokens

Claude Fable 5$0.650Fits in one request
GPT-5.4$0.170Fits in one request

GPT-5.4 costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5$2.50Fits in one request
GPT-5.4$0.650Fits in one request

GPT-5.4 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 GPT-5.4
SpecificationAnthropic Claude Fable 5OpenAI GPT-5.4
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJune 9, 2026March 5, 2026
Context window1M1.05M
Input $/Mtok$10.00$2.50
Output $/Mtok$50.00$15.00
Coding index79.364.4
Independent measurements behind it63
Cost per solved task$2.16$1.02
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5 better than GPT-5.4 for coding?

Pick Claude Fable 5 for coding: it scores 79.3 on the Vibe Coding Index against 64.4 for GPT-5.4. Pick GPT-5.4 for output tokens 3.3x cheaper ($15.00 vs $50.00 per million) and a lower cost per solved task ($1.02 against $2.16).

Which is cheaper, Claude Fable 5 or GPT-5.4?

Claude Fable 5 costs $10.00 per million input tokens and $50.00 per million output tokens; GPT-5.4 costs $2.50 and $15.00. Per solved SWE-bench Verified task, Claude Fable 5 costs $2.16 and GPT-5.4 $1.02.

Which has the bigger context window, Claude Fable 5 or GPT-5.4?

GPT-5.4, with 1.05M tokens against 1M.

How many benchmarks is the Claude Fable 5 vs GPT-5.4 comparison based on?

100 benchmarks have a result for both models as of October 21, 2026. Claude Fable 5's coding index rests on 6 independent benchmarks and GPT-5.4's on 3. Where only one model has a result, the page says so instead of naming a winner.

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