GPT-5.5-Pro

GPT-5.5-Pro was released by OpenAI on Thursday, Apr 23 2026.

GPT-5.5-Pro was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.

GPT-5.5-Pro costs $30.00 per million input tokens and $180.00 per million output tokens through the OpenAI API. Rates are pay-as-you-go API prices verified against OpenAI's published pricing on August 18, 2026.

GPT-5.5-Pro reports 7 tracked benchmark scores — BullshitBench v2: 36%; Next.js Evals: 65%; BrowseComp: 90.1%; Humanity's Last Exam (with tools): 57.2%; FrontierMath (Tier 1–3): 52.4%; FrontierMath (Tier 4): 39.6%; GDPval (win/tie rate): 82.3%. Scores are the figures published at release by OpenAI. It holds the best score among all models tracked here on FrontierMath (Tier 1–3) and FrontierMath (Tier 4).

No. GPT-5.5-Pro is a proprietary model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

OpenAI's previous tracked release was GPT-5.5 on Apr 23 2026. It was followed by GPT-5.5-Cyber on Jun 22 2026.