GPT-5.5 Pro vs GPT-5.6 Terra
GPT-5.5 Pro vs GPT-5.6 Terra: which AI model is cheaper, has the larger context window and more capabilities? Side-by-side comparison updated daily.
Quick verdict
- GPT-5.6 Terra is 15× cheaper than GPT-5.5 Pro for the same mix of input and output tokens.
- Both have the same context window.
- GPT-5.6 Terra is the more recent release (Jul 9, 2026).
- GPT-5.5 Pro scores higher on independent tests (overall index 162.5 vs 159.3).
- Choose GPT-5.6 Terra if cost matters most; choose GPT-5.5 Pro if you need its specific strengths above. For the best results, test both on your own prompts.
| GPT-5.5 Pro | GPT-5.6 Terra | |
|---|---|---|
| Company | OpenAI | OpenAI |
| Released | Apr 24, 2026 | Jul 9, 2026 ● |
| Overall index | 162.5 ● | 159.3 |
| GPQA Diamond | — | 93.3% |
| AIME math | — | 100% |
| FrontierMath | 87.7% ● | 86.0% |
| SimpleQA Verified | — | 43.2% |
| Input (per 1M tokens) | $30 | $2 ● |
| Output (per 1M tokens) | $180 | $12 ● |
| Cost for 1M input + 1M output tokens | $210 | $14.00 ● |
| Providers | 2 | 7 ● |
| Context | 1.1M | 1.1M |
| Max output | 128K | 128K |
| Inputs | Files, Image, Text | Files, Image, Text |
| Outputs | Text | Text |
| Reasoning | ✓ | ✓ |
| Tool use | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Open weights | — | — |