Overview
GPT-5.5 Pro is OpenAI’s high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads. It features a 1M+ token context window (922K input, 128K output) with support for...
Our take
In the tier of frontier assistants aimed at high-stakes professional work, this model sits at the premium end, positioned for deep reasoning and accuracy on complex, high-stakes workloads. The specs back the framing: a 1,050,000-token context window (922K input, 128K output), vision, chain-of-thought reasoning, tool calling and structured JSON output, with a 2025-12-01 knowledge cutoff among the most recent listed. A legal or financial team analysing a large evidence set where an error carries real cost is the scenario it targets, trading speed and price for reliability on hard problems. That trade is stark against its alternatives. At $30.00 per 1M input tokens it is by far the costliest option here, well above Claude Sonnet 5 and the general Claude, ChatGPT and Gemini assistants, and Sakana Fugu Ultra offers a similar large window for a fraction of the price, so the case rests entirely on whether peak accuracy justifies the premium. There is no free tier. The feature set matches its siblings; what you pay extra for is the accuracy-first tuning rather than any capability the cheaper GPT-5.5 variants lack. Ideal for research and writing teams handling complex, high-consequence tasks where getting it right outweighs cost. Choose it when accuracy on hard problems justifies the price; for routine work or cost-sensitive volume, the standard GPT-5.5 or a rival model delivers the same features for far less.
How OpenAI: GPT-5.5 Pro stacks up
Among the 372 chatbots & llms tools in our directory, it ranks #3 of 367 on quality (9.2/10), 14% above the 367-tool average of 8.0, and its $30/1M input-token rate is in the premium end — 1442% pricier than the 355-model average of $1.95/1M.
Weighing quality against cost, OpenAI: GPT-5.5 Pro's cost-per-quality-point of $3.26 places it at #343 of 346 for value among chatbots & llms tools.
OpenAI: GPT-5.5 Pro in depth
OpenAI: GPT-5.5 Pro, built by OpenAI, sits in the chatbots & llms space and is a paid tool starting at $30.00/1M tokens. Our editors rate it 9.2 out of 10 based on capability, ecosystem and value. It handles a context window of 1,050,000 tokens.
On the feature side, OpenAI: GPT-5.5 Pro brings 1,050,000-token context window, vision (image input), reasoning / chain-of-thought and tool / function calling. These are the capabilities that most shape day-to-day use and separate it from thinner alternatives.
Its biggest strength is large 1,050,000-token context window, bigger than most models listed here, while the main trade-off to weigh is that above-average api pricing ($30 per 1m input tokens). Keep both in mind when deciding whether it fits your workflow.
OpenAI: GPT-5.5 Pro is most often chosen for research and writing. If that matches your goals, it's a strong candidate to shortlist.
Key features
- ✓1,050,000-token context window
- ✓Vision (image input)
- ✓Reasoning / chain-of-thought
- ✓Tool / function calling
- ✓Structured (JSON) outputs
- ✓Knowledge cutoff 2025-12-01
Pricing
Pros
- +Large 1,050,000-token context window, bigger than most models listed here
- +Built-in reasoning (chain-of-thought) mode for harder problems
- +Accepts images as input (vision-capable)
- +Supports tool / function calling for agent-style workflows
Cons
- −Above-average API pricing ($30 per 1M input tokens)
Who should use OpenAI: GPT-5.5 Pro
- →Anyone looking for a chatbots & llms tool from OpenAI.
- →Teams and individuals focused on research and writing.
- →People who value large 1,050,000-token context window, bigger than most models listed here.
- →Workflows that need a 1,050,000 tokens context window.
Who should look elsewhere
- →Anyone who needs a free tier — this tool is paid only.
- →Those for whom above-average api pricing ($30 per 1m input tokens) is a dealbreaker.
Best for
10 Best OpenAI: GPT-5.5 Pro Alternatives in 2026
OpenAI: GPT-5.5 Pro is a strong chatbots & llms tool, but it is not the only option. Whether you are after a lower price, different features or a better fit for your workflow, here are the 10 best alternatives to OpenAI: GPT-5.5 Pro, ranked and compared.
Anthropic
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OpenAI
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Google DeepMind
Gemini is Google's natively multimodal model family, deeply integrated across Search, Workspace, Android and the Pixel…
Stepfun
Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B…
Anthropic
Claude Haiku 5.5 is Anthropic's small, fast model for high-volume, cost-sensitive work such as summarization…
Mistral AI
Mistral Large 4 is a frontier multimodal (text and image input) model from Mistral AI built for reasoning, coding, and…
OpenAI
GPT-6.1 Sol Pro is the same underlying model as [GPT-6.1 Sol](https://openrouter.ai/openai/gpt-6.1-sol), served with…
OpenAI
GPT-6.1 Sol is an upgrade to GPT-6 Sol from OpenAI, positioned below the flagship GPT-6 Astra in the GPT-6 series.
Anthropic
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a…
Fireworks
Ember-1 is a specialized reasoning model from Fireworks Research, built on [Kimi…
OpenAI: GPT-5.5 Pro vs top alternatives
A side-by-side look at how OpenAI: GPT-5.5 Pro stacks up against its closest rivals.
| Feature | OpenAI: GPT-5.5 ProOpenAI | ClaudeAnthropic | ChatGPTOpenAI | GeminiGoogle DeepMind |
|---|---|---|---|---|
| Quality score | 9.2 / 10 | 9.6 / 10 | 9.5 / 10 | 9.2 / 10 |
| Starting price | $30.00/1M tokens | $20/mo | $20/mo | $20/mo |
| Free tier | No | Yes — Free tier available | Yes — Free tier available | Yes — Free tier available |
| API input price | $30 / 1M tokens | $0.1 / 1M tokens | $2 / 1M tokens | $0.75 / 1M tokens |
| API output price | $180 / 1M tokens | $0.5 / 1M tokens | $10 / 1M tokens | $3.75 / 1M tokens |
| Speed | — | Fast | Fast | Fast |
| Context window | 1,050,000 tokens | 200K tokens | 128K tokens | 1M-2M tokens |
| Categories | Chatbots & LLMs | Chatbots & LLMs, Coding, Writing | Chatbots & LLMs, Coding, Writing | Chatbots & LLMs, Coding, Writing |
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Frequently asked questions
Q. Is OpenAI: GPT-5.5 Pro free?
No — OpenAI: GPT-5.5 Pro is a paid tool, starting at $30.00/1M tokens.
Q. How much does OpenAI: GPT-5.5 Pro cost?
OpenAI: GPT-5.5 Pro starts at $30.00/1M tokens. API usage is around $30 per 1M input tokens and $180 per 1M output tokens.
Q. What is OpenAI: GPT-5.5 Pro best for?
OpenAI: GPT-5.5 Pro is best suited to research and writing, within the chatbots & llms category.
Q. What are the best OpenAI: GPT-5.5 Pro alternatives?
Popular alternatives to OpenAI: GPT-5.5 Pro include Claude, ChatGPT, Gemini and StepFun: Step 5 Preview. Each trades off price, quality and ecosystem differently.
Q. Is there a free alternative to OpenAI: GPT-5.5 Pro?
Yes. Claude, ChatGPT, Gemini offer a free tier, making them good starting points if you want to avoid an upfront subscription.
Q. Why switch from OpenAI: GPT-5.5 Pro?
Common reasons include pricing, specific feature gaps (Above-average API pricing ($30 per 1M input tokens)), data-privacy requirements, or simply wanting a tool that fits your stack better.
How we rate AI tools
Our quality score weighs capability on real tasks, breadth of features and integrations, pricing and value, and how actively the tool is maintained. Scores are editorial guidance, not benchmarks — always trial a tool on your own workflow before committing. Pricing and features change frequently, so verify current details on the official site.
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