Last updated: April 5, 2026 · Reviewed by Daniel Ashford
🔥GPT-5.3 Codex vs ⚡Gemini 2.5 Flash
Head-to-head across 6 dimensions · by Daniel Ashford
Summary
GPT-5.3 Codex leads overall with an Index of 95.2 vs 82.5. GPT-5.3 Codex wins on accuracy, reasoning, safety, coding, creativity, instruction. On pricing, Gemini 2.5 Flash is more affordable.
❓ Frequently Asked Questions
Is GPT-5.3 Codex better than Gemini 2.5 Flash?
Based on the LLM Judge Index™, GPT-5.3 Codex scores higher overall (95.2 vs 82.5). GPT-5.3 Codex leads on accuracy, reasoning, safety, coding, creativity, instruction, while Gemini 2.5 Flash leads on no dimensions.
Which is cheaper, GPT-5.3 Codex or Gemini 2.5 Flash?
Gemini 2.5 Flash is more affordable at $0.15/M tokens.
Which is better for coding?
GPT-5.3 Codex scores higher on coding (97 vs 80).
Which model is safer?
GPT-5.3 Codex has a higher safety score (93 vs 88).