Gemini 4 Carbon: Google's New Top Model, and When You Can Use It

Update, November 11, 2026: Gemini 4 Carbon became generally available on the paid Gemini API on November 10, at the introductory $2 / $10 until November 30, and Google AI Ultra now includes it in the Gemini app. Google AI Pro stays on Argon. Google announced Gemini 4 Carbon on October 28, 2026, and on day one you could not use it. Carbon launched first on the Artificial Analysis Intelligence Index v5.0 with a score of 59, one point ahead of Claude Opus 5.5. Since November 9 it is second: on v5.0.1, Anthropic’s Claude Fable 5.2 leads at 64.6 against Carbon’s 60.0. Google gave it first to a subset of cyber defenders, and developers and Ultra subscribers got it 13 days later.

Carbon arrives just two weeks after Gemini 4 Argon opened to the public, and Google pitches it at the same work: long software engineering jobs and cybersecurity defense. This guide covers who can use Gemini 4 Carbon and on which plan. It also covers the price, and how Carbon's benchmarks compare with Argon, Claude Opus 5.5 and GPT-6 Astra.

The Key Takeaways

• Second on the board: Gemini 4 Carbon scores 60.0 on the Artificial Analysis Intelligence Index v5.0.1, behind Claude Fable 5.2 at 64.6 and ahead of Claude Opus 5.5 at 59.1 and GPT-6 Astra at 56.9. It launched first, at 59 on v5.0.
• Public since November 10: after a first release to cyber defenders in Google's Fairwind Program, Carbon is generally available on the paid Gemini API and in AI Studio, and Google AI Ultra includes it in the Gemini app.
• Same price as Argon: an introductory $2 per million input tokens and $10 per million output tokens, rising to $4 and $20 after November 30, 2026, the same date as Argon.
• Argon on AI Pro: Google AI Pro subscribers get Gemini 4 Argon, not Carbon; Carbon in the Gemini app needs Google AI Ultra. Both models went from defenders-only to public in 13 days.

What Is Gemini 4 Carbon?

Gemini 4 Carbon is Google's newest frontier model and, in Google's announcement, "our strongest model with state-of-the-art cybersecurity and long horizon capabilities." Carbon is the second public model of the Gemini 4 generation. The first, Gemini 4 Argon, was announced on September 30, 2026 and opened to paying users on October 13.

Google built Gemini 4 Carbon for long, multi-step engineering work. The announcement says Google's internal teams "have seen Carbon run for days" on hard bugs. The examples are finding the root cause of subtle bugs across large codebases and low-level systems, then patching them. Google also says it improved Carbon at agentic work, scientific tasks, full-stack web development and multimodal understanding, building on user feedback from Argon.

The name was not a surprise to people following the Gemini 4 rollout. Business Insider reported on October 9 that Google employees were testing a new internal version of Gemini 4 called Carbon, and our Gemini 4 tracker had logged that report as unverified. The October 28 announcement confirms Carbon as a real, named model, not an internal codename that disappeared.

Google's official account announced Gemini 4 Carbon with the same headline claims as the blog post, including the staged rollout:

Introducing Gemini 4 Carbon, our latest frontier model.

Carbon delivers improved performance across domains — ranking #1 on v5.0 of the @ArtificialAnlys Intelligence Index and sets a new state-of-the-art in cybersecurity and long-horizon capabilities.

It’s rolling out starting this week to cyber defenders through our Fairwind Program, with expanded access coming soon 🧵

— Google (@Google) October 28, 2026

Can You Use Gemini 4 Carbon Yet?

Yes, since November 10, 2026. On launch day, October 28, Carbon was not in the Gemini app, in AI Mode in Search, or on the public Gemini API: Google gave it first "to a subset of cyber defenders", then to "additional trusted partners." On November 10 Google made it generally available on the paid tier of the Gemini API and in Google AI Studio, and its subscriptions page lists "Highest access to Gemini 4 Carbon" in the Gemini app for Google AI Ultra. Google AI Pro lists Argon, not Carbon, and Carbon is not on the free API tier.

Who Gets Gemini 4 Carbon First: the Fairwind Program

The first Gemini 4 Carbon users come from Google DeepMind's Fairwind Program. Google describes Fairwind as early access for "high-priority defenders (like governments, healthcare providers, and telecommunications services)" and says it works with more than 650 partners globally.

Fairwind is not a waitlist an individual can join. Google DeepMind runs background checks on organizations that apply. The program's published terms, written for Argon, say partners must use phishing-resistant multi-factor authentication, limit model access to internal cybersecurity, incident response or penetration testing teams, and may not share, redistribute or sell access. Partners may only run permitted dual-use tasks, such as authorized threat simulation, reverse engineering and malware analysis for defense or academic research.

Google also says it is "actively engaged in the U.S. government's voluntary process for pre-release model testing." The cyber-first rollout follows the same logic as Argon. Carbon is good at finding and exploiting software flaws, so Google wants defenders to have it first.

When Gemini 4 Carbon Was Released to Everyone

Google made Gemini 4 Carbon generally available on November 10, 2026, 13 days after announcing it, the same gap the Gemini 4 Argon rollout set. Google announced Argon on September 30, 2026 for Fairwind cyber defenders only. On October 13, 13 days later, Google opened Argon to the paid Gemini API and to Google AI Pro and Ultra subscribers in the Gemini app and AI Mode in Search. Ultra subscribers also got it in Google Antigravity and AI Studio.

This article's launch-day estimate, a public release around mid-November based on Argon's 13 days, held. Sundar Pichai's launch post had asked people to "hang tight" and promised "wider availability soon":

I did say we'd be releasing our models periodically...introducing Gemini 4 Carbon, our next frontier model.

Following Argon's release just two weeks ago, Carbon shows the pace at which we’re pushing the frontier, it ranks #1 on the recently updated v5.0 of @ArtificialAnlys Intelligence Index at 59. It also leads across key cybersecurity evaluations scoring 88.2% on SEC-bench Pro for finding vulnerabilities, 54.8% on ExploitGym for exploitation, and 71.0% on CWE-bench for patching.

We’re seeing significant improvements in long-horizon tasks even compared to Argon, and we’ve strengthened frontier safeguards.

As we did with Argon, we’re going to roll it out gradually + responsibly. Some trusted cyber defenders will get access starting this week. We'll be expanding it to more partners through our Fairwind Program, ahead of wider availability soon, so hang tight!

— Sundar Pichai (@sundarpichai) October 28, 2026

What to Use If You Are on Google AI Pro

On Google AI Pro the strongest Gemini is still Gemini 4 Argon, because Carbon in the Gemini app needs Google AI Ultra. On the paid Gemini API, both cost the same introductory $2 and $10 per million tokens. Free and Google AI Plus users do not get Argon; Plus subscribers get Gemini 4 Hydrogen, the faster Gemini 4 model released on November 12, and free users get it only when Auto picks it. Our Gemini 4 Argon guide covers its plans, limits and benchmarks in full. Need a strong model for writing, research or coding on a Mac this week? Fello AI puts Gemini, Claude and GPT in one app, so you can keep working with what is available instead of waiting on one vendor's rollout.

Gemini 4 Carbon Pricing

Gemini 4 Carbon costs an introductory $2 per million input tokens and $10 per million output tokens on the Gemini API, with cached input tokens 95% off. That is the same introductory price as Gemini 4 Argon. A footnote in Google's announcement says that after the introductory period, "the price of $4 per 1M input tokens and $20 per 1M output tokens will apply."

Google's API changelog now dates the introductory period: it runs through November 30, 2026, the same as Argon's, with $4 and $20 from December 1. Independent evaluator Vals AI already lists Gemini 4 Carbon at the later $4 and $20 rates, so expect to see both prices quoted.

For Gemini app users the question is which plan, not which token price. Google's subscriptions page lists Gemini 4 Carbon for Google AI Ultra, which starts at $99.99 a month, and not for Google AI Pro, which gets Argon. This article had guessed both plans would get it; only Ultra did.

Gemini 4 Carbon Benchmarks

Gemini 4 Carbon launched at the top of the broadest independent benchmark available: Artificial Analysis Intelligence Index v5.0 listed Gemini 4 Carbon (High) first at 59, followed by Claude Opus 5.5 (Max) at 58. Artificial Analysis published v5.0 on October 27, the day before Carbon. On v5.0.1, re-read on November 10, Carbon scores 60.0 and sits second, behind Claude Fable 5.2 (Max) at 64.6, which Anthropic released on November 9. It is a harder rescale built from nine evaluations, so v5.0 scores cannot be compared with older index numbers. Our explainer on how AI benchmarks work covers what composite indexes like this one measure.

Google's Cybersecurity Numbers

Google's headline Gemini 4 Carbon scores are on cybersecurity, and Google ran all three external evaluations without guardrails. That means the public version, which ships with safety filters, may not score the same.

Google adds internal results it does not publish in full. It says Gemini 4 Carbon has more than twice Argon's success rate at generating secure code. It also says the Chrome team found Carbon "more than 10X better than another lab's large frontier model" at producing high-quality patches. Google does not name the rival lab, so that comparison cannot be checked.

What Independent Testers Found

Independent results mostly back Google, with one caveat on factual accuracy. Vals AI ranks Gemini 4 Carbon third of 36 models on its Vals Index (November 9) at 70.45%, behind Claude Fable 5.2 at 71.31% and Claude Sonnet 5.5 at 70.85%, and ahead of Claude Opus 5.5 at 70.14%. On Artificial Analysis’s AA-Omniscience knowledge test Carbon scores 54, five points ahead of Opus 5.5, though Claude Fable 5.2 has since taken the top score at 67.

The caveat sits inside that same AA-Omniscience test. Gemini 4 Carbon's hallucination rate is 11%, up from Argon's 4%. Carbon still has the second-lowest hallucination rate Artificial Analysis lists, behind only Argon, but it answers wrongly more often than its predecessor when it does not know. Google's internal testing points the other way. It says Carbon "cuts unsupported claims by approximately 2x over Argon." The two results measure different things and do not cancel out, so check Carbon's factual answers the way you would check any model's.

Gemini 4 Carbon vs Argon vs Claude Opus 5.5 vs GPT-6 Astra

Gemini 4 Carbon is the second-highest-scoring model on the Artificial Analysis Intelligence Index v5.0.1, behind Claude Fable 5.2, and every model around it is one you can actually use. Carbon leads Claude Opus 5.5 by less than a point.

The nine-point jump from Gemini 4 Argon to Gemini 4 Carbon is the real story for Google users. Argon trailed both Claude Opus 5.5 and GPT-6 Astra on the v5.0 index; Carbon edges past both. Google's own comparison chart is less one-sided than the headline, though. In that chart GPT-6 Astra still leads the FrontierSWE 2 coding test (65.5% against Carbon's 61.2%), and Claude Opus 5.5 leads the OSWorld-2.1 computer-use subset (87.2% against 81.5%). Carbon leads the other 15 of the 17 rows.

Gemini 4 Carbon Safety: What Google Says Changed

Gemini 4 Carbon uses the same safety stack as Argon, according to Google: model training, real-time misuse defenses, prompt-injection resistance and chain-of-thought monitoring. Google says it went further on alignment with Carbon, and reports these internal results:

All five figures are Google's own measurements. No outside lab has published matching numbers yet, and as of October 28 Google's model card page lists Gemini 4 Argon but no card for Gemini 4 Carbon.

The Verdict on Gemini 4 Carbon

Gemini 4 Carbon put Google back at the top of the independent rankings, two weeks after Argon trailed Claude Opus 5.5 and GPT-6 Astra by seven points or more. It held first place for twelve days, until Claude Fable 5.2 passed it on November 9, and it still leads Opus 5.5 and Astra. Since November 10 that lead is no longer on paper, because Carbon is on the paid API and in Google AI Ultra. The catches are that AI Pro does not get it, the price doubles after November 30, and its factual-accuracy record is mixed. Google’s next generation is further out: our Gemini 5 release date guide estimates it between July and October 2027.

If you pay for Google AI Ultra, switch to Carbon in the Gemini app; on Google AI Pro, Argon is still the strongest Gemini you get. On the API, Carbon costs the same as Argon until November 30, so test it there first. If you need the best model you can use today, Claude Fable 5.2 scores higher than Carbon and is available now, while Claude Opus 5.5 and GPT-6 Astra sit one and three points behind Carbon at a lower price.

Frequently Asked Questions

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