OpenAI: GPT-5.5 wins on more metrics (5 of 9), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | Anthropic: Claude Sonnet 4.6 | OpenAI: GPT-5.5 |
|---|---|---|
| Intelligence Index | 42.6 | 56.7✓ |
| Coding Index | 43.0 | 56.2✓ |
| GPQA Diamond | 80% | 93%✓ |
| Design Arena Elo | 1329 | 1355✓ |
| Speed (tokens/sec) | 44✓ | 40 |
| Latency | 1.3s✓ | 3.9s |
| Input price /M | $3.00✓ | $5.00 |
| Output price /M | $15.00✓ | $30.00 |
| Context window | 1M | 1.1M✓ |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSONVision |