Question 1

What is GPT-5.5?

Accepted Answer

GPT-5.5 is a large language model from OpenAI, released on 15 March 2026. OpenAI’s 2026 flagship — strongest at reasoning, coding and tool use.

Question 2

When was GPT-5.5 released?

Accepted Answer

GPT-5.5 was released by OpenAI on 15 March 2026.

Question 3

How much does GPT-5.5 cost?

Accepted Answer

GPT-5.5 costs $5.00 per 1 million input tokens and $15.00 per 1 million output tokens via OpenAI’s API. At a typical 3:1 input/output ratio the blended cost works out to about $7.50 per 1M tokens.

Question 4

How smart is GPT-5.5?

Accepted Answer

GPT-5.5 scores 82 out of 100 on our intelligence index — a frontier-tier composite of MMLU, MMLU Pro, GPQA, MATH and HumanEval benchmark scores. That places it #1 of 22 language models we track.

Question 5

What is the context window of GPT-5.5?

Accepted Answer

GPT-5.5 has a 400k-token context window — roughly 300,000 words of text. That’s what you can fit into a single request (your prompt plus all uploaded documents and the model’s response combined).

Question 6

What is GPT-5.5 best for?

Accepted Answer

GPT-5.5 is most useful for agentic workflows, complex coding and hard math & research. Its key strengths are best-in-class reasoning, huge 400k context and strong tool use and agents.

Question 7

How fast is GPT-5.5?

Accepted Answer

GPT-5.5 generates around 95 output tokens per second with a typical time-to-first-token of 420 ms on the major API providers. Reasoning models that "think" before answering will appear slower on tokens-per-second since they spend time on internal chain-of-thought.

Question 8

Is GPT-5.5 better than Claude 4 Opus?

Accepted Answer

GPT-5.5 scores higher on our intelligence index (82 vs 81). On most general tasks GPT-5.5 has the edge — but Claude 4 Opus can still be the better pick on cost or specific capabilities. See our full GPT-5.5 vs Claude 4 Opus comparison at /ai-models/compare/gpt-5-5-vs-claude-4-opus/.

Question 9

What is the best alternative to GPT-5.5?

Accepted Answer

The closest alternatives to GPT-5.5 are Claude 4 Opus, Gemini 2.5 Pro and OpenAI o1. Each shares most of GPT-5.5’s use-cases — pick by price, context window or specific capability rather than headline intelligence.

Question 10

Is GPT-5.5 open source?

Accepted Answer

No. GPT-5.5 is proprietary — the weights are not released. Access is via OpenAI’s own API and partner platforms. For open-weights alternatives in the same tier, see our open-source AI models page.

Question 11

Can I use GPT-5.5 for free?

Accepted Answer

The consumer ChatGPT product offers free, rate-limited access to a version of GPT-5.5 and DALL·E 3. The OpenAI API itself is paid — though new accounts get a small starting credit. Microsoft Copilot also bundles GPT access at no extra cost on some tiers.

GPT-5.5

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