Last updated: April 5, 2026 · Reviewed by Daniel Ashford
🔥GPT-5.3 Codex vs ⚡Gemini 2.5 Ultra
Head-to-head across 6 dimensions · by Daniel Ashford
Summary
GPT-5.3 Codex leads overall with an Index of 95.2 vs 93.0. GPT-5.3 Codex wins on accuracy, reasoning, coding, creativity, instruction. Gemini 2.5 Ultra wins on safety. On pricing, Gemini 2.5 Ultra is more affordable.
❓ Frequently Asked Questions
Is GPT-5.3 Codex better than Gemini 2.5 Ultra?
Based on the LLM Judge Index™, GPT-5.3 Codex scores higher overall (95.2 vs 93.0). GPT-5.3 Codex leads on accuracy, reasoning, coding, creativity, instruction, while Gemini 2.5 Ultra leads on safety.
Which is cheaper, GPT-5.3 Codex or Gemini 2.5 Ultra?
Gemini 2.5 Ultra is more affordable at $7/M tokens.
Which is better for coding?
GPT-5.3 Codex scores higher on coding (97 vs 91).
Which model is safer?
Gemini 2.5 Ultra has a higher safety score (94 vs 93).