GPT-5.5 Pro vs Grok-4 Heavy
OpenAI vs xAI — benchmarks, pricing, and capabilities side by side.
| GPT-5.5 Pro | Grok-4 Heavy | |
|---|---|---|
| Intelligence index | — | 89.3 |
| Developer | OpenAI | xAI |
| Type | Multimodal | Multimodal |
| Access | API only | API only |
| Context window | 1,050,000 tokens | — |
| Input price | $30.00 / 1M | — |
| Output price | $180.00 / 1M | — |
| Speed | — | — |
| Released | April 24, 2026 | July 9, 2025 |
| Parameters | — | — |
| Input modalities | Image, Text | — |
| Output modalities | Text | — |