GPT-5.3-Codex vs o3 Pro
OpenAI vs OpenAI — benchmarks, pricing, and capabilities side by side.
- •GPT-5.3-Codex has the higher intelligence index (91.5 vs 84.5)
- •GPT-5.3-Codex is cheaper ($1.75 vs $20.00 per 1M input)
- •GPT-5.3-Codex is faster
- •GPT-5.3-Codex has a larger context window (400K)
| GPT-5.3-Codex | o3 Pro | |
|---|---|---|
| Intelligence index | 91.5 | 84.5 |
| Developer | OpenAI | OpenAI |
| Type | Multimodal | Multimodal |
| Access | API only | API only |
| Context window | 400,000 tokens | 200,000 tokens |
| Input price | $1.75 / 1M | $20.00 / 1M |
| Output price | $14.00 / 1M | $80.00 / 1M |
| Speed | 73 tok/s | 25 tok/s |
| Released | February 24, 2026 | June 10, 2025 |
| Parameters | — | — |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
Shared benchmarks
GPT-5.3-Codex
o3 Pro
GPQA Diamond
91.5
84.5