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    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
    1M
    Estimated · 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
    56points
    Estimated · As of Aug 11, 2026Stale · 31d old
    GPQA Diamond
    96%
    Estimated · As of Aug 11, 2026Stale · 31d old

    Speed and latency

    Output speed
    52tokens/s
    Estimated · 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

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    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.