All modelsOpenAI
GPT-5.5 Pro
Higher-effort Pro tier. Wins on HLE with tools and FrontierMath.
FrontierProprietary400K contextReleased Apr 2026textvisionaudio-inaudio-outcode
API price · per 1M tokens
$15/$60
input / output
≈ $26.25/M blended
Benchmarks
Bar shows this model's score; tick shows the best score across all tracked models for context.
SWE-bench VerifiedReal GitHub issues, human-verified patches. The standard coding-agent benchmark.
90.1/ best 90.1Best in class
SWE-bench Pro2,294 harder real-world GitHub issues. Where the frontier separates now.
63.0/ best 69.2Terminal-Bench 2.xAgentic command-line workflows — planning, iteration, tool coordination.
84.0/ best 84.0Best in class
GPQA DiamondGoogle-proof graduate-level science Q&A. General reasoning proxy.
94.4/ best 94.4Best in class
MMLU-ProMulti-task language understanding across 120+ academic subjects.
93.0/ best 93.0Best in class
HumanEval+Functional code generation from docstrings.
96.0/ best 96.0Best in class
MATH-500Competition-style math problems.
97.8/ best 97.8Best in class
Humanity's Last ExamHardest reasoning benchmark (with tools). ~50% = near frontier.
57.2/ best 57.9AIME 2025American Invitational Mathematics Examination.
96.5/ best 96.5Best in class