OpenAI's previous frontier model for complex professional workloads, built on GPT-5.4 with stronger reasoning and higher reliability.
Anthropic's fifth-generation Sonnet — near-Opus intelligence at Sonnet speed and price.
No shared demos for these models yet.
No captured outputs for these models yet.
Based on the Capability Index, GPT 5.5 scores higher (89.6 vs 80.1). However, "better" depends on your use case — pricing, speed, context window, and specific capability needs all matter.
Claude Sonnet 5 has a lower blended cost. GPT 5.5: $5.00 input / $30.00 output. Claude Sonnet 5: $2.00 input / $10.00 output.
GPT 5.5 has a larger context window: GPT 5.5 supports 1.1M tokens vs Claude Sonnet 5 at 1M tokens.
Yes, both GPT 5.5 and Claude Sonnet 5 support vision/image input.
Key differences: GPT 5.5 has a notably higher capability index (9.5 point gap); Claude Sonnet 5 is significantly cheaper. Compare full specs on this page.
If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both GPT 5.5 and Claude Sonnet 5 for free on idapt.app to see which performs better for your specific needs.