Claude 3 Opus vs OpenAI Codex Mini

Compare Claude 3 Opus by Anthropic against OpenAI Codex Mini by OpenAI, context windows of 200K vs 200K, tested across 8 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or OpenAI Codex Mini?

Claude 3 Opus and OpenAI Codex Mini are both competitive models. Claude 3 Opus costs $15/M input tokens vs $1.5/M for OpenAI Codex Mini. Context windows: 200K vs 200K tokens. Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and OpenAI Codex Mini

Claude 3 Opus is made by anthropic while OpenAI Codex Mini is from openai. Claude 3 Opus has a 200K token context window compared to OpenAI Codex Mini's 200K. On pricing, Claude 3 Opus costs $15/M input tokens vs $1.5/M for OpenAI Codex Mini.

Our Verdict
Claude 3 Opus
Claude 3 Opus
OpenAI Codex Mini
OpenAI Codex Mini

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

OpenAI Codex Mini is 13x cheaper per token — worth considering if cost matters.

Too close to call
vs

Ask them anything yourself

Claude 3 OpusOpenAI Codex Mini

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
Free preview13 of 58 slides
FAQ

Common questions