GPT-5.5
OpenAI's previous flagship, still served but superseded by the GPT-5.6 tiers.
GPT-5.5 specifications
| Provider | OpenAI |
|---|---|
| Context window | 1,050,000 tokens (1.1M) |
| Input price | $5.00 / 1M tokens |
| Output price | $30.00 / 1M tokens |
| Inputs | Text, Images |
| Reasoning mode | Yes |
| Vision (image input) | Yes |
| Tool / function calling | Yes |
| Native real-time web | No |
| Open-weight | No |
| Released | April 2026 |
Pricing & context web-verified August 2026 — confirm on OpenAI's pricing page. Previous flagship, still served. Prompts over 272K input tokens bill at 2x input and 1.5x output for the whole request.
What GPT-5.5 is best for
- Agentic, multi-step workflows
- Computer use and tool orchestration
- Document and image understanding
- Production coding
How to prompt GPT-5.5
- Give it a goal and a set of tools, then let it plan and self-verify rather than scripting every step.
- Use JSON mode / structured outputs when you need machine-readable results.
- Front-load instructions before long context — it follows directions placed first more reliably.
- Prompts over 272K input tokens bill at 2x input and 1.5x output for the whole request; trim context where you can.
Work with GPT-5.5
- Build an optimized prompt with the OpenAI prompt generator.
- Estimate cost with the token counter & cost calculator, or compare every model on the AI model comparison page.
- Related reading: Best Chatgpt Prompts 2026 · Gpt 5 Coding Prompts.
- Official: chatgpt.com
- Other OpenAI models: GPT-5.6 Sol · GPT-5.6 Terra · GPT-5.6 Luna · GPT-5.4 nano.
Frequently asked questions
What is GPT-5.5's context window?
GPT-5.5 has a 1,050,000-token context window (about 1.1M tokens) — the maximum amount of text it can consider at once.
How much does GPT-5.5 cost?
Via the OpenAI API, GPT-5.5 costs $5.00 per 1M input tokens and $30.00 per 1M output tokens (web-verified August 2026). Output tokens cost more, so the length of the model's reply usually drives the bill.
Is GPT-5.5 multimodal?
Yes — GPT-5.5 accepts Text, Images as input, not just text.
Is GPT-5.5 open-weight?
No — GPT-5.5 is available only through the OpenAI API, not as downloadable weights.