OpenAI
GPT-5.5 Thinking
The GPT-5.5 reasoning option introduced in ChatGPT on April 23, 2026 for complex professional work. Reasoning summaries can help explain an answer, but do not expose the model's raw hidden reasoning. This is a historical ChatGPT variant; availability and usage limits depend on the product and plan.
1M tokens
Multimodal
Max
- Provider
- OpenAI
- Context
- 1MEstimated · As of Aug 11, 2026Stale · 31d old
- yno subscription tier
- Max
- Released
- Apr 23, 2026
- Speed
- Slow
- Reasoning
- Expert
- Modality
- Multimodal
Benchmarks
Quality
- AA Intelligence Index
- 56pointsEstimated · As of Aug 11, 2026Stale · 31d old
- GPQA Diamond
- 96%Estimated · As of Aug 11, 2026Stale · 31d old
Speed and latency
- Output speed
- 52tokens/sEstimated · As of Aug 11, 2026Stale · 31d old
API pricing
Not available
AA measurements unavailable
Indexes use points; evaluations use accuracy percentages. API measurements do not measure yno application performance. Methodology
Capabilities
- Reasoning
- Mathematics
- Science
- Reasoning Summaries
Use cases
- Math proofs
- Scientific reasoning
- Step-by-step analysis
- Verification tasks
Strengths
- Reasoning summaries
- Complex problem-solving
- Math and science tasks
- Extended reasoning
Best for
Historical comparisons of GPT-5.5 reasoning in ChatGPT and analysis that benefits from reasoning summaries
Use GPT-5.5 Thinking in yno.ai
No credit card required
Related models
Frequently asked
- What is GPT-5.5 Thinking?
- The GPT-5.5 reasoning option introduced in ChatGPT on April 23, 2026 for complex professional work. Reasoning summaries can help explain an answer, but do not expose the model's raw hidden reasoning. This is a historical ChatGPT variant; availability and usage limits depend on the product and plan.
- How much does GPT-5.5 Thinking cost in yno.ai?
- GPT-5.5 Thinking is available on the Max tier of yno.ai.
- What can GPT-5.5 Thinking do?
- GPT-5.5 Thinking is best for Historical comparisons of GPT-5.5 reasoning in ChatGPT and analysis that benefits from reasoning summaries. Its main capabilities include Reasoning, Mathematics, Science, Reasoning Summaries.
- How does GPT-5.5 Thinking compare to other models?
- GPT-5.5 Thinking excels at Reasoning summaries and is recommended for Math proofs, Scientific reasoning, Step-by-step analysis, Verification tasks. See related models below.
- How do I use GPT-5.5 Thinking in yno.ai?
- Sign up for yno.ai, select GPT-5.5 Thinking from the model picker, and start chatting.