GPT-5.5 vs o3
Direct spec comparison of GPT-5.5 (from OpenAI) and o3 (from OpenAI). Want a 3- or 4-way comparison? Open the multi-model tool →
 GPT-5.5OpenAI | o3 OpenAI | |
|---|---|---|
| Vendor | OpenAI | OpenAI |
| Family | GPT | o-series |
| Release date | 2026-04-23 | 2025-04-16 |
| Context window | 400,000 tokens | 200,000 tokens |
| Parameters | — | — |
| Modality | text, vision, audio | text, vision |
| License | proprietary | proprietary |
| Source | proprietary | proprietary |
| Description | OpenAI's smartest and most intuitive model — successor to GPT-5, with major coding, research, and document workflow gains. GPT-5.5 Pro variant also available for heavier reasoning. | Reasoning-focused model in the o-series. |
| Links | ||
| Benchmarks | ||
| MMLU-Pro | 87.6% | — |
| GPQA-D | 89.4% | 87.7% |
| HumanEval | 96.8% | — |
| Aider | 89.7% | — |
| AIME-25 | 94.2% | 88.9% |
| LiveCB | 78.9% | — |
| MMMU | 78.4% | — |
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