GPT-5.5 Instant: benchmarks, price and rank
GPT-5.5 Instant from OpenAI is 90th of 123 rated AI models on Spezia's leaderboard. It costs $5 in, $30 out per million tokens.
- 90th of 123 rated models
- Rating 878
- Rated on 6 benchmarks
- Closed
- Released May 5, 2026
- 400,000 tokens of context
- Knows the world to August 2025
Where it is strongest
Not in the top tenth on any benchmark in use.
Where it falls behind
- 18th of 19 on HealthBench Professional
- 62nd of 66 on FrontierMath Tier 4
- 67th of 76 on FrontierMath
Price: $5 in, $30 out per million tokens.
Its headline results
The benchmarks that count most in the rating, with its place among the models measured the same way, and where each number came from.
- FrontierMath26.3%
Hundreds of new, unpublished math problems written by mathematicians, from hard undergraduate level up to research, with answers a computer can check.
67th of 76. Independent result from Epoch AI.
- MMMU-Pro76%
College exam questions that need a picture to answer, such as charts, diagrams, maps and chemical structures, with more answer options than the original MMMU and some questions shown only as a screenshot.
28th of 51. The maker's own number, from OpenAI, via LLM Stats.
- CharXiv Reasoning81.6%
Questions about real charts from scientific papers that need reasoning across the chart, not just reading off a value.
22nd of 45. The maker's own number, from OpenAI, via LLM Stats.
- LMArena text1,419
People put a question to two anonymous models and vote for the better answer.
69th of 107. Independent result from LMArena.
- HealthBench Professional38.4%
Conversations in the style of real clinicians' chats with AI, graded against rubrics written by physicians.
18th of 19. The maker's own number, from OpenAI, via LLM Stats.
- HealthBench51.4%
5,000 realistic health conversations with patients and clinicians, each graded against criteria written by 262 physicians.
14th of 16. The maker's own number, from OpenAI, via LLM Stats.
- GPQA Diamond82.5%
Graduate-level questions in biology, physics and chemistry, written by PhDs so that searching the web does not give the answer away.
83rd of 103. Independent result from Epoch AI.
- FrontierMath Tier 42.4%
Research-level problems that take professional mathematicians days.
62nd of 66. Independent result from Epoch AI.
1 more results in its full profile.
Every result with its source, what it costs per task, what jumped with its release, side by side with any other model, and answers to your questions about when to use it.
Models ranked near it
How the rating works, and every benchmark it uses: the model leaderboard.