Claude Opus vs GPT-5.3-Codex
Anthropic vs OpenAI — benchmarks, pricing, and capabilities side by side.
- •GPT-5.3-Codex is cheaper ($1.75 vs $5.00 per 1M input)
- •Claude Opus has a larger context window (1M)
| Claude Opus | GPT-5.3-Codex | |
|---|---|---|
| Intelligence index | — | 91.5 |
| Developer | Anthropic | OpenAI |
| Type | Multimodal | Multimodal |
| Access | API only | API only |
| Context window | 1,000,000 tokens | 400,000 tokens |
| Input price | $5.00 / 1M | $1.75 / 1M |
| Output price | $25.00 / 1M | $14.00 / 1M |
| Speed | — | 73 tok/s |
| Released | April 21, 2026 | February 24, 2026 |
| Parameters | — | — |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |