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Claude Fable 5 vs Grok 4.5

Full profiles: Claude Fable 5 (Anthropic) and Grok 4.5 (SpaceXAI): every benchmark, price and rank.

Updated · Data from 13 sources

As of 26 Oct 2026, Claude Fable 5 (max) leads on quality (69.3 vs 60.0 on the BenchLeader Index), but Grok 4.5 costs 6.7× less, so it is the better buy unless you need the extra quality. Claude Fable 5 leads in every category we measure both in.

Claude Fable 5 benchmarks max Anthropic Grok 4.5 benchmarks SpaceXAIOpen in the comparison tool

Which to pick for…

The pick's numbers come first. Category scores on the BenchLeader scale (50 is the average model, 15 points one standard deviation). High confidence means a lead of half a standard deviation or more; under one point is called either.

Use casePickWhyConfidence
CodingClaude Fable 574 vs 57 category score; WeirdML 91.9% vs 46.4%High
Agents & tool useClaude Fable 565 vs 57 category score; LiveBench Agentic Coding 62.2% vs 56.5%High
MathsClaude Fable 572 vs 65 category score; LiveBench Mathematics 96.0% vs 90.8%Medium
ReasoningClaude Fable 574 vs 69 category score; SimpleBench 81.9% vs 70.0%Medium
Chat quality (human preference)–Only Grok 4.5 has an Arena rating (65 category score)Not comparable
Lowest costGrok 4.5$3.00 vs $20.00 per 1M blended; agentic coding session $0.144 vs $0.800–
Fastest first answerGrok 4.51.5 s (Grok 4.5) vs 101.8 s (Claude Fable 5 (max)) to the first answer token–
High volume on a budgetNeither flagshipA smaller model is usually the better fit: Cheapest good LLMs, Fastest LLMs–

Key differences

  • Claude Fable 5 (max) leads on quality: 69.3 vs 60.0.
  • Claude Fable 5 (max) is stronger in agents & tools, coding, composite, instruction following, knowledge, long context, maths, reasoning.
  • Grok 4.5 is stronger in human preference, multimodal.
  • Grok 4.5 is 6.7× cheaper ($3.00 vs $20.00 per 1M blended).

At a glance

SpecClaude Fable 5Grok 4.5
DeveloperAnthropicSpaceXAI
Released9 Jun 20268 Jul 2026
Context window (tokens)1,000,000500,000
Compared atClaude Fable 5 (max)Grok 4.5
Open weightsNoNo
Price in / out / cached input per 1M$10.00 / $50.00 / $1.00$2.00 / $6.00 / $0.300

Category by category

Category scores on the BenchLeader scale: 50 is the average evaluated model, 15 points is one standard deviation. A gap under one point is called level.

CategoryClaude Fable 5 (max)Grok 4.5Leader
Reasoning73.868.7Claude Fable 5
Coding73.857.1Claude Fable 5
Agents & tools65.056.5Claude Fable 5
Maths72.465.4Claude Fable 5
Knowledge81.0–not comparable
Instruction following63.1–not comparable
Human preference–65.4not comparable
Multimodal–62.9not comparable
Long context66.3–not comparable
Composite85.0–not comparable

Where sources disagree

Across the 11 benchmarks both have, Claude Fable 5 leads 11, Grok 4.5 leads 0. Every overall index that rates both puts Claude Fable 5 ahead.

Overall indexClaude Fable 5 (max)Grok 4.5Leader
BenchLeader Index69.360.0Claude Fable 5
AA Intelligence Index v4.3.249.638.8†Claude Fable 5
Arena Text1503†1466Claude Fable 5

Each publisher runs its own tasks, harnesses and effort settings, so their overall verdicts can differ; BenchLeader reconciles them on one scale. † measured at another effort setting of the same model (the publisher did not test the one compared here).

Price, speed and latency

List prices blended at three input tokens per output token. Per-task prices use the token counts on the methodology page; suite cost is what Artificial Analysis paid to run its whole Intelligence Index.

MeasureClaude Fable 5 (max)Grok 4.5
Blended price per 1M tokens$20.00$3.00
Input / output per 1M$10.00 / $50.00$2.00 / $6.00
Cached input per 1M$1.00$0.300
Price per task: chat reply$0.019$0.0026
Price per task: summarize a 30-page report$0.150$0.028
Price per task: code edit$0.135$0.021
Price per task: agentic coding session$0.800$0.144
Price per task: structured extraction$0.030$0.0052
Cost to run a full benchmark suite$8.75–
Output speed67 tok/s54 tok/s
Time to first answer101.8 s1.5 s
Time to a complete answer109.3 s–

Each model is compared at its best-ranked reasoning-effort setting. Claude Fable 5 (max) scores 69.3 and takes 102 s to its first answer token; Claude Fable 5 scores 66.6 in 4 s, Claude Fable 5 (high) scores 64.4 in 4 s. Grok 4.5 scores 60.0 and takes 2 s to its first answer token; Grok 4.5 (high) scores 59.3 in 12 s. Higher effort means more thinking before the answer: better scores, longer waits and more tokens billed. How reasoning effort changes scores and cost.

Every benchmark

122 benchmarks, grouped by category; each name links to the board and its leaders. † measured at another effort setting of the same model, shown for reference and not counted as a win.

MetricPublisherClaude Fable 5 (max)Grok 4.5
BenchLeader IndexBenchLeader69.360.0
Agents & tools scoreBenchLeader65.056.5
Coding scoreBenchLeader73.857.1
Composite scoreBenchLeader85.0–
Instruction following scoreBenchLeader63.1–
Knowledge scoreBenchLeader81.0–
Long context scoreBenchLeader66.3–
Maths scoreBenchLeader72.465.4
Reasoning scoreBenchLeader73.868.7
Human preference scoreBenchLeader–65.4
Multimodal scoreBenchLeader–62.9
Blended price $/MBenchLeader$20.00$3.00
Output speedBenchLeader67 tok/s54 tok/s
Time to first answerBenchLeader101.8 s1.5 s
Context windowBenchLeader1,000,000 tokens500,000 tokens
Reasoning
GPQA DiamondEpoch AI Benchmarking Hub85.9%93.4%†
SimpleBenchSimpleBench81.9%70.0%
Arena Hard PromptsArena (LMArena)1529†1488
LiveBench 1.0 ReasoningLiveBench89.7%87.2%
GPQA Diamond (AA)Artificial Analysis92.6%93.1%†
Humanity's Last Exam (AA)Artificial Analysis55.5%42.7%†
GPQA Diamond (Vals)Vals AI93.2%†92.9%†
EnigmaEvalScale AI SEAL39.3%†–
Kagi LLM BenchmarkKagi LLM Benchmark88.8%†83.5%
ARC-AGI-1ARC Prize98.5%85.7%†
ARC-AGI-2ARC Prize89.2%52.6%†
ARC-AGI-3ARC Prize–0.3%†
CritPtArtificial Analysis28.6%15.4%†
Chess PuzzlesEpoch AI Benchmarking Hub47.0%35.0%†
Mystery Game PuzzlesEpoch AI Benchmarking Hub52.0%–
LMCAEpoch AI Benchmarking Hub60.3%45.2%†
DTBenchEpoch AI Benchmarking Hub98.4%96.5%†
ForecastBenchForecastBench66.0%66.1%†
BTF-3Epoch AI Benchmarking Hub13.0%†–
Coding
SciCodeSciCode61.0%55.0%†
WeirdMLWeirdML91.9%46.4%
FrontierCodeCognition53.5%†42.4%
GSO-BenchGSO-Bench78.4%†–
Arena CodingArena (LMArena)1551†1514
Arena WebDevArena (LMArena)1624†1553
Show all 122 benchmarks
MetricPublisherClaude Fable 5 (max)Grok 4.5
Coding
LiveBench 1.0 CodingLiveBench86.0%68.6%
LiveCodeBenchVals AI89.8%†87.3%†
IOIVals AI–40.6%†
SWE-bench (Vals)Vals AI95.0%†86.6%†
Code MigrationVals AI55.1%†36.6%†
ProgramBenchVals AI2.0%†0.0%†
Vibe Code Bench v1.1Vals AI90.3%†69.0%†
SWE Atlas: Codebase QnAScale AI SEAL39.0%†–
SWE Atlas: RefactoringScale AI SEAL54.8%†–
SWE Atlas: Test WritingScale AI SEAL55.6%†–
MirrorCodeEpoch AI Benchmarking Hub63.9%†–
Surface Evolver BenchEpoch AI Benchmarking Hub95.0%†74.4%†
DeepSWE v1.1Epoch AI Benchmarking Hub69.7%53.8%†
ALE-BenchEpoch AI Benchmarking Hub2041.3†1309.3†
FrontierSWEEpoch AI Benchmarking Hub47.0%–
Terminal-Bench 4.0 (AA)Artificial Analysis42.4%10.6%†
Terminal-Bench 2.1 (AA)Artificial Analysis84.6%81.7%†
Startrise FrontendStartrise73.8%†68.0%
Agents & tools
Terminal-BenchTerminal-Bench44.5%12.4%†
Remote Labor IndexScale AI / CAIS15.8%†–
APEX-AgentsMercor63.6%†56.2%
Arena AgentArena (LMArena)7.8†–
LiveBench Agentic CodingLiveBench62.2%56.5%
Terminal-Bench HardArtificial Analysis62.9%–
τ²-Bench Telecom (AA)Artificial Analysis98.5%–
Terminal-Bench 2.1 (Vals)Vals AI80.5%†67.8%†
MCP AtlasScale AI SEAL83.3%†–
HiL-BenchScale AI SEAL56.3%†–
τ³-bench Bankingτ²-bench39.7%47.9%†
τ³-Banking (AA)Artificial Analysis38.1%42.1%†
Analyst Agent (AA)Artificial Analysis48.8%35.0%†
CyberBenchVals AI–71.0%†
Finance Agent v2Vals AI56.3%†48.4%†
Harvey's Legal Agent Benchmark v1Vals AI11.3%†12.9%†
Legal Research BenchVals AI49.5%†38.0%†
SkillsBenchVals AI–66.0%†
SREBenchVals AI–0.8%†
Tax Agent BenchVals AI38.3%†24.9%†
Terminal-Bench 4.0 (Vals)Vals AI41.4%†8.6%†
Terminal-Bench ScienceVals AI15.7%†–
Time Horizon Index: KSPVals AI–6.3%†
Web Search IndexVals AI46.9%†35.5%†
Arena SearchArena (LMArena)1229†1206
PostTrainBenchEpoch AI Benchmarking Hub41.8%23.4%†
GBAEvalEpoch AI Benchmarking Hub74.5%†65.4%
Vending-Bench 2Andon Labs4966.63887.4
AutomationBenchArtificial Analysis54.1%57.9%†
GDP.pdf (AA)Artificial Analysis24.0%18.8%†
EnterpriseOps-GymArtificial Analysis51.1%40.8%†
AA-Briefcase v1.1Artificial Analysis15371278†
FACTS SearchGoogle–79.4%
Maths
FrontierMath Tiers 1–3Epoch AI Benchmarking Hub87.0%57.2%†
FrontierMath Tier 4Epoch AI Benchmarking Hub90.2%24.4%†
OTIS Mock AIMEEpoch AI Benchmarking Hub99.7%97.8%†
ProofBenchVals AI95.0%31.0%†
LiveBench MathematicsLiveBench96.0%90.8%
Arena MathsArena (LMArena)1521†1473
Knowledge
SimpleQA VerifiedEpoch AI Benchmarking Hub70.7%†48.3%†
LiveBench 1.0 Data AnalysisLiveBench80.5%73.0%
AA-OmniscienceArtificial Analysis43.325.3†
MMLU-ProVals AI91.5%†89.2%†
LegalBenchVals AI88.6%†86.0%†
CorpFinVals AI71.8%†67.4%†
TaxEvalVals AI76.9%†71.7%†
PRBench FinanceScale AI SEAL53.9%†–
PRBench LegalScale AI SEAL52.6%†–
Excel Modeling BenchmarkVals AI73.7%†52.9%†
MedCodeVals AI56.1%†43.3%†
MedScribeVals AI88.5%†86.9%†
Public Benefits Bench v1.1Vals AI70.4%†–
EBR-benchEpoch AI Benchmarking Hub39.5%–
GDP.pdfEpoch AI Benchmarking Hub29.8%14.0%†
AA-Omniscience: accuracyArtificial Analysis65.3%51.5%†
AA-Omniscience: non-hallucinationArtificial Analysis36.4%45.9%†
Instruction following
LiveBench LanguageLiveBench90.7%82.8%
LiveBench Instruction FollowingLiveBench75.8%71.5%
IFBenchArtificial Analysis63.5%–
Arena Instruction FollowingArena (LMArena)1508†1461
Human preference
Arena TextArena (LMArena)1503†1466
EQ-Bench 4EQ-Bench1310†–
Arena Creative WritingArena (LMArena)1501†1452
Arena Multi-turnArena (LMArena)1517†1473
Arena Longer QueriesArena (LMArena)1522†1480
Multimodal
Arena VisionArena (LMArena)1325†1287
MMMU-ProArtificial Analysis–80.4%†
MMMU-Pro (Vals)Vals AI89.3%†61.8%†
MortgageTaxVals AI68.9%†61.8%†
SAGEVals AI51.9%†35.0%†
Blueprint-Bench 2Epoch AI Benchmarking Hub38.6%†27.3%
Long context
AA-LCRArtificial Analysis82.3%79.3%†
Arena DocumentArena (LMArena)1499†1464
MLCRArtificial Analysis20.6%16.1%†
Composite
Epoch Capabilities IndexEpoch AI Benchmarking Hub163.4†154.1
LiveBench 1.0LiveBench83.0%75.8%
AA Intelligence Index v4.3.2Artificial Analysis49.638.8†
Vals RSI IndexVals AI24.3%–
Vals Multimodal IndexVals AI74.2%†63.4%†

Data as of 2026-10-26. Best configuration of each model; every score links to its source on the model pages.

What changed

  • Grok 4.5: BenchLeader Index 58.8 → 60.0.
  • Claude Fable 5 (max): 1 new result (Vals RSI Index).
  • Claude Fable 5 (max): 1 score revision.
  • Claude Fable 5 (max): 1 new result (ForecastBench).
  • Grok 4.5: 6 new results (LiveBench 2.0, LiveBench Long Agentic, LiveBench 2.0 Coding…).
  • Claude Fable 5 (max): 4 new results (GDPval-AA v2.1, AA-Omniscience: accuracy, AA-Omniscience: non-hallucination…).
  • Grok 4.5: 1 new result (Startrise Frontend).
  • Claude Fable 5 (max): 1 score revision.
  • Grok 4.5: 1 score revision.
  • Claude Fable 5 (max): BenchLeader Index 64.6 → 69.1.

Rankings: Best LLM overall · Best LLM for coding · Best LLM for agents · Best cheap LLMs

Claude Fable 5 vs Grok 4.5: questions

Is Claude Fable 5 better than Grok 4.5?
Claude Fable 5 (max) leads on quality: 69.3 vs 60.0. The BenchLeader Index combines every independent quality benchmark; Claude Fable 5 (max) is ahead overall as of 2026-10-26, but check the category scores for your use.
Which is cheaper, Claude Fable 5 or Grok 4.5, and will that change?
Grok 4.5 is cheaper today: $3.00 against $20.00 per million tokens, blended at three input tokens per output token. No price change has been announced for either.
Is Claude Fable 5 better than Grok 4.5 for coding?
Claude Fable 5 scores higher in coding (74 vs 57 on the category index, where 50 is average). On WeirdML, the top shared coding benchmark, it is 91.9% for Claude Fable 5 against 46.4% for Grok 4.5.
Is Claude Fable 5 better than Grok 4.5 for agents and tool use?
Claude Fable 5 scores higher in agentic tasks (65 vs 57 on the category index, where 50 is average).
Which is better for long documents?
Claude Fable 5 accepts more context: 1,000,000 against 500,000 tokens for Grok 4.5.
Which has lower latency?
Grok 4.5 answers first: 1.5 s against 101.8 s to the first answer token, as Artificial Analysis measures it. Reasoning effort drives most of this: a higher setting thinks longer before it answers.
Which is faster, Claude Fable 5 or Grok 4.5?
Claude Fable 5 streams faster: 67 against 54 output tokens per second.
Do independent benchmarks agree on Claude Fable 5 vs Grok 4.5?
Across the 11 benchmarks both have, Claude Fable 5 leads 11, Grok 4.5 leads 0. Every overall index that rates both puts Claude Fable 5 ahead.
When was Grok 4.5 released?
Grok 4.5 was released on 8 Jul 2026.