GPT-5.1 Codex Max vs Claude Opus 5.5
30-second takeaway
- GPT-5.1 Codex Max has the cheaper input: $1.25 vs $4 (per 1M tokens, 69% less)
- Claude Opus 5.5 has the larger context: 1M vs 400K tokens
| GPT-5.1 Codex Max Abacus | Claude Opus 5.5 AI/ML API | |
|---|---|---|
| Input | $1.25 | $4 |
| Output | $10 | $20 |
| Context | 400K | 1M |
More specs (max output / capabilities)
| max output | 128,000 | 128,000 |
| Reasoning | ✓ Yes | ✓ Yes |
| Tool calls | ✓ Yes | ✓ Yes |
| Open weights | — No | — No |
Prices are official/data-source rates (per 1M tokens), not what relays actually charge — relay prices vary with discounts and group multipliers. See methodology.