Gemini 4 Carbon: Google opens its strongest AI model to paying users

Google opened up Gemini 4 Carbon, the model it calls its strongest, on 10 November 2026. In a post dated that day, the company said Carbon is now available to all paying developers and enterprises through its API, and is rolling out to Google AI Ultra subscribers in the Gemini app, AI Mode in Search and its Antigravity coding tool.

Until this week the model was limited to a small group of cybersecurity defenders. The wider release comes with a low introductory price that Google says will double after 30 November 2026.

What is Gemini 4 Carbon?

Carbon is the larger of the two models in Google's Gemini 4 family. The other, Gemini 4 Argon, launched about two weeks earlier, and was added to AI Mode for Google AI Pro and Ultra subscribers on 13 October 2026, according to Search Engine Roundtable.

Google's post, written by Koray Kavukcuoglu of Google DeepMind, describes Carbon as its strongest model, with what it calls frontier performance in cybersecurity and in long-running agentic work. That means tasks where the model plans and carries out many steps with little supervision. Our explainer on what agentic AI is covers the idea in more detail.

Google does not present Carbon as a replacement for Argon. The post says Argon remains the ideal choice for the majority of software engineering and knowledge work. Carbon is aimed at harder problems, such as complex multi-step coding and open-ended scientific research, and Google says it uses more tokens than Argon to explore, reason and check its own work.

Google's developer documentation lists the model under the code gemini-4-carbon, with a context window of 1 million tokens and support for text, image, audio, video and PDF.

What changed on 10 November?

Google first announced the model on 28 October 2026. At that point it said it would make Carbon available to a subset of cyber defenders and extend access gradually to trusted partners through its Fairwind Program. It said it was still gathering feedback and working on guardrails before a wider release, and described its rollout as deliberate.

Reuters reported the same day, in a story carried by Khaleej Times, that the model would go first to a subset of cybersecurity defenders. 9to5Google reported that it was officially "coming soon" to developers, businesses and consumers, with no date given.

The 10 November post supplies that date. Roughly two weeks after the restricted launch, the general version is on sale.

Who can use it, and where?

According to Google's post, access now breaks down as follows.

Group	Where Carbon is available	Condition
Developers	Gemini API in Google AI Studio and Android Studio	Paid tier
Enterprises	Gemini for business (API or model menu), Google Antigravity, CodeMender	Paying customers
Consumers	Gemini app, AI Mode in Search, Google Antigravity	Google AI Ultra subscription
Scientists	Google Antigravity, free for six months	Apply for a chance at access, subject to eligibility, capacity and selection
Cyber defenders	"Carbon for cyber" through the Fairwind Program	By application, on a rolling basis

Two points stand out. First, Ultra is the only consumer plan Google names. Argon went to both Pro and Ultra subscribers; the Carbon post does not mention Pro.

Second, there is no free route for developers. Google's pricing page states that the model is not available on the free tier.

In Search, Carbon appears as an option in the AI Mode model selector for paid subscribers, Search Engine Roundtable reported. It quoted Google's Robby Stein writing on X: "Shipping Gemini 4 Carbon in Search today for Google AI Ultra subs!"

How much does it cost?

For API users, Google has set the same introductory price as Argon.

API price per 1 million tokens	Until 30 November 2026	From 1 December 2026
Input	$2	$4
Output (including thinking tokens)	$10	$20
Batch input	$1	$2
Batch output	$5	$10

The figures come from Google's pricing page and match the footnote in its blog post, which adds that the price applies to the Carbon model intended for public access only.

Google has not published sterling prices for the API, and we have not converted the figures. Its post does not set out usage limits for Ultra subscribers in the Gemini app or AI Mode, so those remain unconfirmed.

What does Google say it is good at?

All of the performance figures below are Google's own claims or come from tests it has chosen to cite. None has been independently verified by Mainstream Tech.

• Coding and automation. Google says Carbon ranks first on CursorBench 4.0, Perplexity's WANDR and Zapier's AutomationBench, at more than two times lower cost per task than the next best model from another company.
• Security. It says the model reached 100% recall on scanning and 95% precision on triage on an internal Google benchmark. The strongest cyber results it cites apply to the version reached through the Fairwind Program.
• Honesty. On a 375-task test of honesty in agentic work, Google says Carbon passed 92% of tasks, against 70% for Argon.

Google is also previewing a feature called /swarm in Antigravity. It says this turns a single prompt into a coordinated team of agents that can be tracked in real time, with Carbon handling design, coordination and auditing while lighter models do the faster work.

What about safety?

The cyber-focused version is handled separately. Google's post directs security teams to apply to the Fairwind Program for access to "Carbon for cyber", and its pricing footnote refers to a distinct model intended for public access. The post does not spell out how the two differ.

For the public release, Google says it has strengthened its misuse safeguards. It reports that Carbon blocked 99% of attack attempts from its own automated red-teaming agent in simulated environments, and that outside tester Trajectory Labs found no new universal jailbreaks across 132 hours and more than 13,000 requests.

The company also concedes a gap. Its post says resistance to prompt injection, where hidden instructions in a web page or document hijack a model, remains an area for continued improvement.

Is Gemini 4 Carbon available in the UK?

Google's announcement does not list countries, so UK availability is not explicitly confirmed in the post itself.

There are two supporting facts. Google's help page for the subscription lists the United Kingdom among the countries where Google AI Ultra is supported. The same page names the Carbon model in AI Mode as a feature that requires users to be 18 or older.

That suggests UK Ultra subscribers are in scope, but Google describes the consumer release as rolling out, so it may not appear for every account at once. UK developers should check the model list in their own AI Studio account.

What does it mean for developers and businesses?

This section is our analysis rather than confirmed fact.

The price window is short. The introductory rate ends on 30 November 2026, about three weeks after launch. Teams that want to compare Carbon with their current model can do so at half the long-term price, but budgets should be planned on the December rate.

Per-token price is not the whole cost. Google says Carbon uses more tokens than Argon on a task. Since output tokens include the model's thinking, a job may cost noticeably more on Carbon even while both models share the same list price. Google's own advice, that Argon suits most work, is a reasonable starting point.

Treat vendor benchmarks as a shortlist, not a verdict. The rankings Google cites are useful signals, but the tests that matter are a company's own tasks and data.

Agent security still needs attention. Google's admission on prompt injection matters most for businesses that let models browse the web, read inboxes or act on internal systems.

Search is changing for paying users first. Publishers and marketers tracking how AI answers affect visibility now have another model to consider in AI Mode, although only on Google's most expensive consumer plan. Our guide to answer engine optimisation explains the wider shift.

Sources

• Google: Gemini 4 Carbon is now available (10 November 2026)
• Google: Gemini 4 Carbon, our next frontier model (28 October 2026)
• Google AI Studio: Gemini API pricing
• Google AI Studio: Gemini models
• Google One Help: Get a Google AI Ultra membership
• Search Engine Roundtable: Gemini 4 Carbon Available In Google Search AI Mode
• Search Engine Roundtable: Gemini 4 Argon In Google Search Via AI Mode
• Reuters via Khaleej Times: Google launches Gemini 4 Carbon AI model with cybersecurity focus
• 9to5Google: Gemini 4 Carbon (28 October 2026)