GPT-5.5 Instant

GPT-5.5 Instant is OpenAI's latest Instant model and the default ChatGPT model released on May 5, 2026. It improves factuality, everyday reasoning, image understanding, STEM answers, concision, conversational tone, and personalization over GPT-5.3 Instant.

HealthBench Consensus

94.7%

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OmniDocBench 1.5

87.5%

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GPQA

85.6%

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CharXiv-R

81.6%

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AIME 2025

81.2%

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MMMU-Pro

76.0%

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HealthBench

51.4%

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HealthBench Professional

38.4%

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HealthBench Hard

22.9%

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