Claude Sonnet 4 vs xAI: Grok 4 Fast (free)
Compare Claude Sonnet 4 by Anthropic against xAI: Grok 4 Fast (free) by xAI, context windows of 200K vs 2.0M, tested across 35 shared challenges. Updated May 2026.
Which is better, Claude Sonnet 4 or xAI: Grok 4 Fast (free)?
Claude Sonnet 4 and xAI: Grok 4 Fast (free) are both competitive models. Claude Sonnet 4 costs $3/M input tokens vs $0/M for xAI: Grok 4 Fast (free). Context windows: 200K vs 2000K tokens. Compare their real outputs side by side below.
Key Differences Between Claude Sonnet 4 and xAI: Grok 4 Fast (free)
Claude Sonnet 4 is made by anthropic while xAI: Grok 4 Fast (free) is from xai. Claude Sonnet 4 has a 200K token context window compared to xAI: Grok 4 Fast (free)'s 2000K. On pricing, Claude Sonnet 4 costs $3/M input tokens vs $0/M for xAI: Grok 4 Fast (free).
Per 1M tokens
No community votes yet. On paper, xAI: Grok 4 Fast (free) has the edge — newer, bigger context window.
Style Comparison
Claude Sonnet 4 uses 87.9x more emoji
