GPT-5

0:48 GPT-5 is the model generation OpenAI launched on Aug 7, 2025 and updated almost every two months until GPT-6 arrived in September 2026: GPT-5.1 (Nov 2025), 5.2 (Dec 2025), 5.3 (Feb and Mar 2026), 5.4 (Mar 2026), 5.5 (Apr 2026) and 5.6 Sol, Terra and Luna (Jul 9, 2026). As of Nov 6, 2026, the GPT-5 models still selectable in ChatGPT's Chat tab are GPT-5.6 Sol and, on Pro, GPT-5.6 Sol Pro; the rest have been retired, and the API is shutting the oldest down on Dec 11, 2026.

Quick facts

GPT-5 (Aug 7, 2025)

3:35 GPT-5 merged OpenAI's chat and reasoning lines into one product. OpenAI described it as a unified system with a fast model, "GPT-5 thinking", and a real-time router that picks between them, and made it the default for all ChatGPT users, replacing GPT-4o, o3, o4-mini, GPT-4.1 and GPT-4.5. GPT-5 pro replaced o3-pro. When limits ran out, a mini version took over. OpenAI's launch scores included 94.6% on AIME 2025 without tools, 74.9% on SWE-bench Verified and 88% on Aider Polyglot, with about 45% fewer factual errors than GPT-4o when using web search. In the API it came as gpt-5, gpt-5-mini and gpt-5-nano on the same day, with GPT-5 Pro added at DevDay on Oct 6, 2025.

Retiring GPT-4o at the same time did not go well: OpenAI later wrote that it restored GPT-4o after feedback from Plus and Pro users. See GPT-4o.

GPT-5.1 to GPT-5.5

The GPT-5.5 launch appears on neither of OpenAI's help-center release-notes pages; its date comes from OpenAI's announcement.

GPT-5.6 Sol, Terra and Luna (Jul 9, 2026)

1:32 GPT-5.6 introduced the size names GPT-6 kept. OpenAI made the family generally available on Jul 9, 2026 as Sol (the flagship), Terra (balanced) and Luna (most cost-efficient), and called GPT-5.6 Sol in ChatGPT "our flagship reasoning model for complex work across coding, research, science, cybersecurity, computer use, and design", for paid plans only. The API added Programmatic Tool Calling with it. Prices fell twice: on Jul 30 Luna by 80% and Terra by 20%, and on Aug 21 Sol "by over 20% for the next 3 months" (OpenAI). That Sol promotion ends "at least through November 21, 2026" by one OpenAI page and on Nov 30, 2026 by the pricing page.

In August, GPT-5.6 Luna became the Free and Go default in ChatGPT, with a Think button, until GPT-6 replaced it in October. A cyber variant, GPT-5.6 Cyber, came with OpenAI's Daybreak program in August 2026 (see GPT-Rosalind and Cyber Models).

Which GPT-5 models remain?

In ChatGPT (Nov 6, 2026): GPT-5.6 Sol remains a separate option in the model menu for paid plans, and Pro has GPT-5.6 Sol Pro (OpenAI Help Center). On Pro $200, the fallback after the weekly GPT-6 Pro limit is GPT-5.6 Thinking at Medium. GPT-5.6 Sol, Terra and Luna stay in ChatGPT Work and Codex. The pricing table still lists "GPT-5 Thinking Mini" on every plan, though OpenAI said in March it would stop being selectable. Everything else is gone:

• GPT-5 (Instant and Thinking): Feb 13, 2026
• GPT-5.1 Instant, Thinking and Pro: Mar 11, 2026
• GPT-5.2 Instant, Thinking and Pro: Jun 12, 2026
• GPT-5.5: retired from ChatGPT, Work and Codex on Oct 14, 2026

The full list is on Retired ChatGPT Models.

In the API: many GPT-5 models are still sold, for example gpt-5.5 at $5 / $30 and gpt-5.4 at $2.50 / $15 per 1M tokens. The first GPT-5 models and o3 shut down on Dec 11, 2026, mapped to gpt-5.6-sol (mini to Terra, nano to Luna); gpt-5.1 and gpt-5.3-codex follow on Apr 1, 2027.

What testers found

17:16 In an Aug 27, 2026 video, Tim Ruscica of Tech With Tim gave GPT-5.6 Sol in the Codex CLI and Anthropic's models in Claude Code the same five coding tasks. On splitting a 5,000-line Python file without breaking it, six of the seven models he ran succeeded and Sol was the fastest, while Claude Opus 5 took 36 minutes, nearly five times as long, partly because it also wrote a tool to prove nothing had broken.

20:45 His conclusion from all five tasks: Codex reached the same correctness much faster, sometimes four to seven times faster than the comparable Anthropic model, with more generous limits and the flagship model on the $20 plan, while Claude went deeper on every task.

Frequently asked questions

When was GPT-5 released? OpenAI released GPT-5 on Aug 7, 2025, to all ChatGPT users and in the API. It replaced GPT-4o, o3, o4-mini, GPT-4.1 and GPT-4.5 as ChatGPT's default.

What is the latest GPT-5 model? GPT-5.6 Sol, Terra and Luna, released Jul 9, 2026, were the last GPT-5 models before GPT-6 Astra arrived on Sep 3, 2026. GPT-5.6 Sol is still selectable in ChatGPT.

Is GPT-5.5 still available? Not in ChatGPT: OpenAI retired GPT-5.5 from ChatGPT, ChatGPT Work and Codex on Oct 14, 2026. It is still in the API at $5 per million input tokens and $30 output, as of Nov 6, 2026.

Can I still use GPT-5 in ChatGPT? The original GPT-5 left ChatGPT on Feb 13, 2026. Its newest successor in the series, GPT-5.6 Sol, remains in the model menu for paid plans.

Sources

• Introducing GPT-5, OpenAI, Aug 7, 2025
• Introducing upgrades to Codex, OpenAI, Sep 15, 2025
• GPT-5.1, OpenAI, Nov 12, 2025
• Introducing GPT-5.2, OpenAI, Dec 11, 2025
• Retiring GPT-4o and older models, OpenAI, Jan 29, 2026
• GPT-5.3 Instant, OpenAI, Mar 3, 2026
• Introducing GPT-5.4, OpenAI, Mar 5, 2026
• Introducing GPT-5.5, OpenAI, Apr 23, 2026
• GPT-5.5 Instant, OpenAI, May 5, 2026
• GPT-5.6, OpenAI, Jul 9, 2026
• API changelog, OpenAI, read Nov 6, 2026
• Deprecations, OpenAI API docs, read Nov 6, 2026
• Pricing, OpenAI API docs, read Nov 6, 2026
• Fast mode, OpenAI API docs, read Nov 6, 2026
• GPT-6 and other models in ChatGPT, OpenAI Help Center, read Nov 6, 2026
• Retiring GPT-4o and other ChatGPT models, OpenAI Help Center, read Nov 6, 2026
• Model Release Notes, OpenAI Help Center, read Nov 6, 2026
• ChatGPT release notes, OpenAI Help Center, read Nov 6, 2026
• ChatGPT pricing, OpenAI, read Nov 6, 2026
• Introducing GPT-5, OpenAI, Aug 7, 2025 (video)
• Meet GPT-5.6, OpenAI, Jul 9, 2026 (video)
• Codex vs Claude - an Honest Comparison, Tech With Tim, Aug 27, 2026 (video)