AI Model Overview

OpenAI GPT-5.6 Sol — what it is, when to use it and what to use instead

Active

No. GPT-5.6 Sol is active at OpenAI and has no announced end date.

gpt-5.6-sol last verified

Summary

GPT-5.6 Sol is OpenAI's flagship model for complex professional work, at $4 per million input tokens and $20 per million output tokens with a 1.05M-token context window and 128K max output. It is the named replacement for the retiring GPT-5 and GPT-5 Pro.

Sol is the flagship of the general GPT-5.6 models, above Terra and Luna; GPT-5.6 Cyber is a separate, access-gated branch of the same line. OpenAI's deprecation page names it as the replacement for gpt-5-2025-08-07, gpt-5-pro-2025-10-06 and gpt-4o-2024-05-13, so most migrations away from the older catalogue land here.

It accepts text and image input and returns text, with reasoning effort from none to max and support for functions, web search, file search and computer use. The knowledge cutoff is 16 February 2026, shared with the other GPT-5.6 models.

No deprecation has been announced.

Modality
  • Text
  • Vision
Use case
  • Chat
  • Coding
  • Reasoning
  • Agents & tool use
  • Long context
  • Web search
Tier
  • Frontier
Access
  • Hosted API

Specifications

Input price
$4.00 / M tokens
Output price
$20.00 / M tokens
Price band
Premium
Context window
1.1M tokens
Max output
128K tokens
Input
Text, image
Output
Text
Knowledge cutoff
February 2026
Tool use
Yes
Structured output
Yes
Weights licence
not published
Model maker
OpenAI

“unknown” means the figure has not been published, or we have not verified it yet — never that the answer is no. “not published” under the weights licence means this model is not offered with downloadable weights. The price band is ours: it bands the blended price (three parts input to one part output) as budget (≤ $0.50), standard (≤ $3), premium (≤ $12) or flagship.

Lifecycle

OpenAI has not announced a deprecation or shutdown date for this model. That is a statement about what has been published, not a guarantee — providers typically announce a shutdown months ahead, and this page updates when they do.

  1. Released
  2. Deprecated not announced
  3. Retired not announced

Use it for

  • Migrate off GPT-5, GPT-5 Pro or GPT-4o before their December 2026 and October 2026 shutdown dates.
  • Run complex professional workloads that need reasoning effort dialled up per request.
  • Process large inputs in one call, up to the 1.05M-token context window.

Avoid it when

  • Your workload is high volume and well defined; GPT-5.6 Terra costs $2 / $12 and GPT-5.6 Luna $0.2 / $1.2 for the same shape of task.
  • You need the newest knowledge; GPT-6 Astra has an April 2026 cutoff against February 2026 here.
  • Your input includes audio or video; GPT-5.6 Sol accepts text and images only.

Alternatives to consider

  • GPT-6 Astra Curated

    OpenAI Active

    The tier above at $10 / $50, 2.5 times the input price, with a newer April 2026 knowledge cutoff.

    $10.00 in · $50.00 out / M tokens 1.1M context

  • GPT-5.6 Terra Curated

    OpenAI Active

    Half the input price at $2 / $12 with the same 1.05M-token window and the same knowledge cutoff.

    $2.00 in · $12.00 out / M tokens 1.1M context

  • Claude Opus 5 Curated

    Anthropic Active

    Anthropic's comparable tier at $5 / $25 with a 1M-token window and a May 2026 knowledge cutoff.

    $5.00 in · $25.00 out / M tokens 1M context

  • Gemini 3.8 Flash Curated

    Google (Gemini) Active

    Google's newest Flash model at $0.75 / $3.75, a fifth of the input price, with audio, video and PDF input.

    $0.75 in · $3.75 out / M tokens 1M context

  • GPT-5.1-Codex-Max Derived

    Microsoft Azure AI Foundry Active

    Alternative from Microsoft Azure AI Foundry, same tier (frontier), similar price; shares chat, coding, reasoning, agents, long-context and search.

    $1.25 in · $10.00 out / M tokens 400K context

Curated suggestions were picked by a reviewer, with the reason written by hand. Derived suggestions are ranked from the data — shared tags, the same tier and a comparable price band — not from benchmark scores. Check the capability fit yourself: we track lifecycle, price and specifications.

Sources

Verified against the source on . Dataset snapshot . Providers can change a date without notice — the link above is always the final word.

About this profile

The specifications and dates above are facts from OpenAI, with the sources listed. The summary, the use-for and avoid-when lists and the curated alternatives are our assessment: editorial profile reviewed on by llm-researcher.

Common questions

What is GPT-5.6 Sol for?
GPT-5.6 Sol is OpenAI's flagship model for complex professional work, at $4 per million input tokens and $20 per million output tokens with a 1.05M-token context window and 128K max output. It is the named replacement for the retiring GPT-5 and GPT-5 Pro.
What does GPT-5.6 Sol cost?
$4.00 per million input tokens and $20.00 per million output tokens, as last verified on 2026-09-10.
What is the context window of GPT-5.6 Sol?
1.1M tokens.
Is GPT-5.6 Sol deprecated?
No. GPT-5.6 Sol is active at OpenAI and has no announced end date.
What should I use instead of GPT-5.6 Sol?
OpenAI GPT-6 Astra — The tier above at $10 / $50, 2.5 times the input price, with a newer April 2026 knowledge cutoff. OpenAI GPT-5.6 Terra — Half the input price at $2 / $12 with the same 1.05M-token window and the same knowledge cutoff. Anthropic Claude Opus 5 — Anthropic's comparable tier at $5 / $25 with a 1M-token window and a May 2026 knowledge cutoff.

All OpenAI models and their end dates →