What is the difference between Claude Fable 5.1 and Grok 4.20 Beta?

Claude Fable 5.1 is developed by Anthropic while Grok 4.20 Beta is developed by xAI. Claude Fable 5.1 has a 1.0M token context window vs Grok 4.20 Beta's 2.0M. You can compare their actual outputs across 10 challenges on Rival to see how they differ in practice.

Which is better, Claude Fable 5.1 or Grok 4.20 Beta?

It depends on your use case. Claude Fable 5.1 and Grok 4.20 Beta each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 10 challenges so you can judge which fits your needs best.

How much does Claude Fable 5.1 cost compared to Grok 4.20 Beta?

Claude Fable 5.1 costs $10/M input tokens and Grok 4.20 Beta costs $2/M input tokens. Grok 4.20 Beta is $8.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Claude Fable 5.1 and Grok 4.20 Beta on Rival?

This page shows a side-by-side comparison of Claude Fable 5.1 and Grok 4.20 Beta across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Updated Sep 2026

Claude Fable 5.1vsGrok 4.20 Beta

Grok 4.20 Beta is cheaper than Claude Fable 5.1 at $2/M vs $10/M input tokens.

Claude Fable 5.1 and Grok 4.20 Beta compared across 10 shared prompts
Spec	Claude Fable 5.1	Grok 4.20 Beta
Input price	$10/M tokens	$2/M tokens
Output price	$50/M tokens	$6/M tokens
Context window	1.0M tokens	2.0M tokens
Weights	Closed	Closed
Free API (OpenRouter)	No	No
Released	Sep 2026	Mar 2026