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GPT-6 Sol
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GPT-6 Sol

GPT-6 Sol (gpt-6-sol) · Family: GPT
The mid-tier model of OpenAI's GPT-6 family, released on 22 September 2026 alongside Luna: an intelligence upgrade at $2/$10 per million tokens — half the price of GPT-5.6 Sol.
✓ Active✓ Public accessLLMMultimodalReasoning modelTool-using model📁 GPT
Release date
22 September 2026
🏢OpenAIProducer
Access:APIHostedDeployment:☁ Cloud

Overview

GPT-6 Sol is the mid-tier model of OpenAI's GPT-6 family, released on 22 September 2026 together with the cheaper GPT-6 Luna — roughly three weeks after the flagship GPT-6 Astra. OpenAI positions both models as combining an intelligence upgrade with cost efficiency, aimed at use cases where Astra is excessive or too expensive.

The model runs under the API identifier gpt-6-sol. Pricing is $2 per million input tokens and $10 per million output tokens. That is exactly half the rates of its predecessor GPT-5.6 Sol, which cost $4 per million input and $20 per million output — a 50% reduction alongside improved capability.

Within the line-up Sol sits in the middle: above the budget GPT-6 Luna ($0.10 and $0.50 per million tokens) and below the flagship GPT-6 Astra, priced at $10 and $50 per million. OpenAI did not publicly state the context window size or detailed benchmark results for Sol in the launch material.

Classification
LLMMultimodalReasoning modelTool-using model
Family: GPT
Access & deployment
APIHosted
Cloud
Weights: Closed
Key parameters
📥 Input: text, image, documents

Technical specification

Modalities
⬇ Input
textimagedocuments
⬆ Output
textcodestructured_data

Capabilities and applications

Native model capabilities
Reasoning
The model's ability to reason logically and solve complex problems.
Category: reasoning
Advanced reasoning
The ability to perform multi-step, structured reasoning: analysing problems, planning steps, and drawing conclusions from hypotheses. Reasoning-first models (e.g. GPT-5.1 Thinking) dedicate a portion of inference to chains of thought before responding.
Category: reasoning
Multi-step reasoning
Carrying out multi-step chains of reasoning across long, complex tasks.
Category: reasoning
Coding
Generating, analysing and modifying code in many programming languages. Covers writing functions, debugging, refactoring, code review, and creating tests. Measured by benchmarks such as HumanEval and SWE-bench.
Category: coding
Agentic capability
The model's ability to autonomously plan and execute multi-step tasks by sequentially using tools, maintaining context, and adapting to intermediate results.
Category: planning
Tool use
The model's ability to call external functions, APIs and tools during a conversation: calculator, search engine, code editor, database. The model decides when and how to use a tool and interprets its result.
Category: planning
Function Calling
Category: planning
Structured output
Producing data in structured formats such as JSON.
Category: structured_generation
Image understanding
Analysing and interpreting the content of images.
Category: vision
Multilingual
Competence in many natural languages (from a few to over a hundred): understanding, generation, translation, and code-switching within a single conversation. Frontier models support a wide range of languages with comparable quality.
Category: language

Pricing

Sources and related pages