GPT-5.1 Thinking

GPT-5.1 Thinking is an OpenAI model available in Quad Chat, with up to 400K tokens of context, image input, tool calling and adjustable reasoning.

GPT-5.1 Thinking at a glance

LabOpenAI
Available onPro plan and up
Context window400K tokens
Max output128K tokens
Image inputYes
Tool callingYes
ReasoningYes
Privacy lanePrivate (Zero Data Retention)

How to use GPT-5.1 Thinking in Quad Chat

  1. Create a free account or sign in.
  2. Open the model picker and choose GPT-5.1 Thinking.
  3. Ask, attach files, or compare the answer with another model.

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Frequently asked questions

Can I use GPT-5.1 Thinking for free?

GPT-5.1 Thinking needs the Pro plan ($15/month) or higher. The Free plan needs no credit card and includes other chat models, so you can try Quad Chat first and upgrade when you need GPT-5.1 Thinking. Yearly billing is 15% less than paying monthly.

What is the context window of GPT-5.1 Thinking?

GPT-5.1 Thinking accepts up to 400K tokens of context and can write up to 128K tokens in one reply, according to the model catalog Quad Chat routes through. Files, pasted text and earlier messages all count toward that window.

Does GPT-5.1 Thinking support images, tools and reasoning?

GPT-5.1 Thinking accepts images as input, so you can attach screenshots, photos and scanned pages. It supports tool calling. It can reason before it answers, with adjustable effort (low, medium and high). You can switch to another model in the same conversation at any time.

Is GPT-5.1 Thinking private in Quad Chat?

GPT-5.1 Thinking runs on the Quad Chat Private Lane, routed to providers under Zero Data Retention terms. Quad Chat does not train models on your conversations, encrypts chats in transit and at rest, and lets you export or delete them at any time.

How much does GPT-5.1 Thinking cost in Quad Chat?

Quad Chat plans have a flat monthly price and draw usage from shared credits, not a per-token bill. The model picker shows an estimate before you send. For reference, the provider's API list price is $1.25 per million input tokens and $10.00 per million output tokens.

Can I compare GPT-5.1 Thinking with other models?

Yes. Send one prompt to GPT-5.1 Thinking and one or two other models, such as GPT-6.1 Sol, GPT-6 and GPT-5.6, and compare the answers side by side in the same thread. You can also switch models mid-conversation without losing your files or context.

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