Gemini 4 Carbon: who gets it, price and what to try first
Google announced Gemini 4 Carbon on 28 October, 15 days after Gemini 4 Argon. It's Google's strongest model, built for long coding jobs and security work. The catch: almost nobody can use it yet. Here's who can, what it will cost, and what to try while you wait.
What Gemini 4 Carbon is
Carbon is the model Google built for jobs that take a long time. Google says its own teams have watched it work for days on one problem, getting past dead ends to find and patch subtle bugs in large codebases. It ranks first on the Artificial Analysis Intelligence Index with 59, and moved up 89 points to fourth place on WebDev Arena, which rates the websites models build.
It isn't first everywhere. In Google's own table GPT-6 Astra still leads FrontierSWE 2, and Claude Opus 5.5 leads OSWorld, the test of using a computer. Treat the table as Google's pitch and wait for people to try it on real work.
Who can use it, and what it will cost
Google is holding Carbon back on purpose. This week it goes to a subset of cyber defenders. Then more trusted partners get it through the Fairwind Program, which only approves organisations, and only for their own security teams. Google is also in the US government's voluntary testing of models before release. Developers, businesses and consumers come "as soon as possible", once the guardrails are tuned. There's no date, and no word on which Gemini plans get it.
The price is set. In the API it starts at $2 per million input tokens and $10 per million output tokens, with cached input 95% off, the same as Argon. After an introductory period it goes up to $4 and $20. Google hasn't said when that period ends for Carbon. For Argon it's 30 November.
What changes: a more careful agent
The part you'll notice day to day is how it behaves on a long task. Google says Carbon makes about half as many claims it can't back up as Argon, and when your files disagree, it shows you the conflict before acting instead of guessing. It oversteps 26% less often and leaves work undone 29% less often.
It also held up against every hidden instruction in Gray Swan's prompt injection test, the kind planted in a web page or email to hijack an agent. That matters more as Gemini reads your mail and connected apps for you.
What to try first, while you wait
On Google AI Pro or Ultra, Argon is in the Gemini app and AI Mode in Search. Give it the kind of job Google built Gemini 4 for: a messy folder turned into a proposal, a long financial report to pick apart, or on a Mac, a coding agent in Antigravity from the Gemini app. (Gemini's notebooks are a good place to keep the files together.)
Then save the prompt. When Carbon arrives, run the same one again, and you'll see for yourself whether it's better on your work, not just on Google's charts. This one tests what Google says Carbon fixed:
A prompt to run on Argon now and Carbon later
Here is a folder of notes and files for a client project. Turn it into a five-slide proposal: the problem, what we'll do, timeline, price and next steps. Where the files disagree or something is missing, list it at the end instead of guessing.
I keep prompts like this in a note so I can rerun them on every new model, as I did for GPT-6 Astra. I make Pinto Notes, a notes app for Mac that ChatGPT, Claude, Claude Code and Codex can read and edit once you allow it (the iPhone app is coming soon). It doesn't connect to Gemini, so there you paste the prompt in.
Questions
When will Gemini 4 Carbon be in the Gemini app?
Google hasn't given a date. It says Carbon comes to developers, businesses and consumers "as soon as possible", after a first group of cyber defenders and more trusted partners have used it and Google has tuned the guardrails. Argon, the Gemini 4 model before it, reached the Gemini app on launch day for Google AI Pro and Ultra.
Is Gemini 4 Carbon free?
Not for anyone yet, because it isn't public. Google hasn't said which Gemini plans will get it. If it follows Argon, expect it on Google AI Pro and Ultra first. For developers it will cost $2 per million input tokens and $10 per million output tokens at launch, then $4 and $20.
What's the difference between Gemini 4 Carbon and Gemini 4 Argon?
Carbon is the newer, stronger model, aimed at long engineering jobs and security work. Google's table puts it ahead of Argon on most tests, for example 65.2% against 57.1% on Terminal-Bench 4.0, and it makes fewer unsupported claims. Argon is the one you can use today.
Can I use Gemini 4 Carbon in the Gemini API?
Not yet. On 28 October the Gemini API's model list had Argon (gemini-4-argon) and no Carbon. Google says developers get it after the first partners. Until then, Argon is on the API's paid tier at the same introductory price.
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