GPT-5.5 Instant
Parameters
Undisclosed
Context Length
1M
Modality
Multimodal
Architecture
Undisclosed
License
Proprietary
Release Date
5 May 2026
Knowledge Cutoff
-
API Pricing (per 1M)
Input: $5.00 · Output: $30.00
Evaluation Benchmarks
Rank
#59
| Benchmark | Score | Rank |
|---|---|---|
General Text | 1474 | 28 |
Graduate-Level QA | 0.856 | 42 |
Agentic Index | 0.19 | 78 |
Intelligence Index | 0.27 | 86 |
Coding Index | 0.39 | 107 |
Rankings
Overall Rank
#59
Coding Rank
#88
About GPT-5.5 Instant
OpenAI's fast daily driver model released May 5, 2026. Features a 1,000,000 token context window, advanced memory source citation mechanics, and tight concise text generations with a massive 52.5% reduction in hallucination profiles. Handled natively in the API via the "chat-latest" alias.
Technical Specifications
Architecture specifications are undisclosed for proprietary models.
Attention
Attention Structure
Multi-Head Attention
Attention Heads
Undisclosed
Key-Value Heads
Undisclosed
Attention Head Dimension
Undisclosed
Position Embedding
Absolute Position Embedding
RoPE Theta
Undisclosed
Sliding Window Attention
Undisclosed
Sliding Window Size
Undisclosed
Sliding Window Ratio
Undisclosed
Linear Attention
Undisclosed
Linear Attention Ratio
Undisclosed
Normalization
Undisclosed
Activation Function
Undisclosed
Dimensions
Hidden Dimension Size
Undisclosed
Number of Layers
Undisclosed
FFN Intermediate Size (Dense)
Undisclosed
Multi-Token Prediction Heads
Undisclosed
Tokenizer
Vocabulary Size
Undisclosed
Resources
About GPT-5.5 Instant
GPT-5.5 Instant is OpenAI's high-speed, cost-efficient default model tier launched globally for ChatGPT and developers. Engineered to dramatically reduce latency and cut hallucinations by over 50% in high-stakes fields like medicine and law, it uses roughly 30% fewer words per response than its predecessor line while supporting integrated memory sources and advanced tool calling.
Other GPT-5.5 Instant Models
- No related models available