Claude Fable 5 vs Grok 4.6

Head-to-head technical comparison of intelligence, capabilities, and API pricing.

Claude Fable 5
Anthropic
AI Mastery Index96.4
LMSYS Arena1507
Technical (MMLU-Pro)95.6%
Cost per 1M Tokens$10
Grok 4.6
xAI
AI Mastery Index93.8
LMSYS Arena1470
Technical (MMLU-Pro)93.1%
Cost per 1M Tokens$2

Which should you use?

Claude Fable 5 leads on the composite index by 2.6 points (96.4 vs 93.8).

Cost is the sharper difference: Claude Fable 5 is 5x the input price of Grok 4.6 ($10 against $2 per 1M), so at volume the choice is usually decided by budget rather than benchmarks.

Pick Claude Fable 5 when

  • Higher composite index — 96.4 against 93.8, a gap of 2.6 points.
  • Ahead on Arena Elo by 37 points (1507 vs 1470), which is outside the board's published confidence intervals.
  • Stronger on MMLU-Pro: 95.6% against 93.1%.

Pick Grok 4.6 when

  • Cheaper input tokens — $2 against $10 per 1M, so Claude Fable 5 costs 5x as much to feed.
  • Better value per point of measured capability: $0.021 per index point against $0.104.

Value per point of measured capability, at list input pricing: Grok 4.6 $0.021 · Claude Fable 5 $0.104 per index point. Run your own token mix through the token cost calculator — a comparison at list price ignores caching and batch discounts, which move real bills more than this gap does.

Our reporting on Anthropic and xAI