Model Comparison
GPT 5.3 Codex vs Opus 5.5
GPT 5.3 Codex ranks #68 on the AI IQ leaderboard with an estimated IQ of 112, while Opus 5.5 ranks #2 on the AI IQ leaderboard with an estimated IQ of 141. The table below puts the two models side by side across the seven capability dimensions, emotional reasoning, cost, speed, and context window.
Where They Sit on the IQ Bell Curve
Both models highlighted on the standard normal IQ distribution of every tracked model
| GPT 5.3 CodexOpenAI | Opus 5.5Anthropic | |
|---|---|---|
| Rank | #68 | #2 |
| IQ | 112 | 141 |
| Abstract Reasoning | 84 | 132 |
| Mathematical Reasoning | 103 | 149 |
| Academic Reasoning | 129 | 138 |
| Programmatic Reasoning | 124 | 154 |
| Computer Use | 113 | 148 |
| Reliability | 115 | 133 |
| Knowledge Work | 113 | 134 |
| Emotional Reasoning | — | — |
| Effective Cost / 1M Tokens | $18.57 | $35.73 |
| Sticker Price / 1M I/O Tokens | $15.75 | $24.00 |
| Speed | 103 tok/s | 98 tok/s |
| Context Window | 400K | 1M |
| Released | 2026-02-05 | 2026-09-22 |
| Open Weights | No | No |
More comparisons
- GPT 5.3 Codex vs Deepseek V4 Pro
- GPT 5.3 Codex vs Fable 5.1
- GPT 5.3 Codex vs Gemini 4 Carbon
- GPT 5.3 Codex vs Glm 5.3
- GPT 5.3 Codex vs GPT 6 Astra
- GPT 5.3 Codex vs Grok 4.7
- GPT 5.3 Codex vs Kimi K3.1 Pro
- GPT 5.3 Codex vs Mimo V2.6 Pro
- GPT 5.3 Codex vs Minimax M3
- GPT 5.3 Codex vs Muse Wonder Full
- GPT 5.3 Codex vs Qwen3.8 Max 0902
- Opus 5.5 vs Deepseek V4 Pro
- Opus 5.5 vs Fable 5.1
- Opus 5.5 vs Gemini 4 Carbon
- Opus 5.5 vs Glm 5.3
- Opus 5.5 vs GPT 6 Astra
- All comparisons