Claude Opus 4.6 vs xAI: Grok 4 Fast (free)
Compare Claude Opus 4.6 by Anthropic against xAI: Grok 4 Fast (free) by xAI, context windows of 1.0M vs 2.0M, tested across 34 shared challenges. Updated April 2026.
Which is better, Claude Opus 4.6 or xAI: Grok 4 Fast (free)?
Claude Opus 4.6 and xAI: Grok 4 Fast (free) are both competitive models. Claude Opus 4.6 costs $5/M input tokens vs $0/M for xAI: Grok 4 Fast (free). Context windows: 1000K vs 2000K tokens. Compare their real outputs side by side below.
Key Differences Between Claude Opus 4.6 and xAI: Grok 4 Fast (free)
Claude Opus 4.6 is made by anthropic while xAI: Grok 4 Fast (free) is from xai. Claude Opus 4.6 has a 1000K token context window compared to xAI: Grok 4 Fast (free)'s 2000K. On pricing, Claude Opus 4.6 costs $5/M input tokens vs $0/M for xAI: Grok 4 Fast (free).
No community votes yet. On paper, Claude Opus 4.6 has the edge — bigger model tier, newer.
Style Comparison
Claude Opus 4.6 uses 20.7x more emoji
vs
Ask them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
