Claude Fable 5 vs Grok 4.20
Claude Fable 5 (Anthropic) and Grok 4.20 (xAI) compared on benchmarks, pricing, context window, and use-case rankings.
- Claude Fable 5 leads on overall intelligence (ECI 163 vs 152).
- Grok 4.20 is cheaper on input tokens — $1.25 vs $10.00 per 1M.
- Grok 4.20 has a larger context window (2M vs 1M tokens).
- Claude Fable 5 ranks higher for coding (96th vs 42th percentile).
| Attribute | Claude Fable 5 | Grok 4.20 |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 163 | 152 |
| Coding | 96 | 42 |
| Math | 96 | 59 |
| Reasoning & Knowledge | 89 | 48 |
| Agentic & Tools | 96 | 55 |
| Specifications | ||
| Developer | Anthropic | xAI |
| Family | Claude | Grok |
| Released | Jun 9, 2026 | Feb 17, 2026 |
| Parameters | — | 500B |
| Availability | API access | API access |
| Context window | 1M | 2M |
| Price — $/M input | $10.00 | $1.25 |
| Price — $/M output | $50.00 | $2.50 |
| Inputs | text, image, file | text, image, file |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 100% | 92% |
| APEX | 45% | — |
| ARC-AGI | 99% | 90% |
| ARC-AGI-2 | 89% | 65% |
| GPQA Diamond | 86% | 89% |
| Humanity's Last Exam | 56% | — |
| SciCode | 61% | — |
| SimpleBench | 82% | — |
| SimpleQA Verified | 71% | 30% |
| WebDev Arena | 1626 | 1374 |
| WeirdML | 92% | 52% |
| τ²-bench | 99% | — |
| Terminal-Bench | — | 57% |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is Claude Fable 5 better than Grok 4.20?
On Epoch AI's Capabilities Index, Claude Fable 5 scores higher (163) than Grok 4.20 (152). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is cheaper, Claude Fable 5 or Grok 4.20?
Grok 4.20 is cheaper on input tokens at $1.25 per million, versus $10.00 (representative OpenRouter pricing).
Which has a larger context window, Claude Fable 5 or Grok 4.20?
Grok 4.20 supports up to 2M tokens, compared with 1M for the other.
Which is better for coding, Claude Fable 5 or Grok 4.20?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Claude Fable 5 ranks higher — 96th vs 42th percentile among the models tracked on Model Beat.
Want a different match-up? Open the compare tool to add or swap models.
More comparisons
Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.