GPT-5.5
OpenAI flagship for the most complex professional work. 1.05M context, reasoning, and vision.
You always get the exact model you pick — we never silently route you to another.
About GPT-5.5
GPT-5.5 is OpenAI's flagship for the most complex professional work — coding, research, and long-horizon agentic tasks — with a 1.05 million token context window, 128,000 max output tokens, and native vision. Official API pricing is $5.00 per million input tokens, $0.50 cached input, and $30.00 output. On just4o.chat it is a Premium+ model that uses 3 premium requests per send before length multipliers, the same generic $30-output ladder as other high-output OpenAI flagships. Reasoning effort can be set to none, low, medium, or high, and the Responses path uses 24-hour prompt cache retention plus medium verbosity, matching the rest of the GPT-5.x family. Prompts over 272K input tokens are billed at 2x input and 1.5x output for the session. The default snapshot is gpt-5.5-2026-04-23; knowledge cutoff is December 1, 2025.
Best for
- Complex professional work — coding, research, and multi-step document or tool-using workflows
- Long-context analysis up to 1.05 million tokens with a 128,000-token output ceiling
- Vision-plus-text tasks that need a flagship OpenAI model rather than a smaller GPT-5.x variant
- Agentic sessions that benefit from 24-hour prompt caching and controllable reasoning effort
Specifications
| Provider | OpenAI |
|---|---|
| Released | 2026-04-23 |
| Intelligence | High |
| Speed | Fast |
| Context window | 1,050,000 tokens |
| Max output | 128,000 tokens |
| Knowledge cutoff | December 1, 2025 |
| Input price | $5.00 / 1M tokens |
| Output price | $30.00 / 1M tokens |
| Request cost | 3 premium requests |
| Plan tier | Premium+ |
| Input | Text, Image |
| Output | Text |
| Features | Cached input: $0.50 / 1M tokens, Prompts over 272K input tokens are billed at 2x input and 1.5x output for the session, Structured outputs, web search, file search, image generation, code interpreter, hosted shell, apply patch, skills, computer use, MCP, and tool search supported |
| API endpoints | v1/chat/completions, v1/responses, v1/batch |
| Model ID | gpt-5.5 |
Frequently asked questions
OpenAI list pricing is $5.00 per million input tokens, $0.50 cached input, and $30.00 output. On just4o.chat it uses 3 premium requests per send before length multipliers.
GPT-5.5 is Premium+, the same access tier as GPT-5.4 and GPT-5.6 Sol — Studio, Aurora, and Pro.
1,050,000 tokens of input context with a maximum of 128,000 output tokens. Prompts over 272K input tokens are billed at 2x input and 1.5x output for the session.
Yes. Reasoning effort can be none, low, medium, or high, and the model accepts text and image inputs with text output.
Both are Premium+ OpenAI flagships with $30/1M output list pricing. GPT-5.6 Sol is hand-tuned to 5 premium requests per send; GPT-5.5 uses the generic output-price ladder and costs 3.