Gemini 4 Carbon: what it does, what it costs and when you can use it

 

Google announced Gemini 4 Carbon on 28 October 2026. It ranks first on the independent Artificial Analysis Intelligence Index v5.0, and Google reports strong cyber defence results. Access starts with selected cyber defenders and Fairwind partners, and Google hasn’t given a date for wider availability.

 

Key takeaways

Carbon scores 59 on the Artificial Analysis Intelligence Index v5.0, up from Argon’s 50
Launch pricing is $2 input and $10 output per million tokens, rising to $4 and $20 later
Access is invite-only for now, starting with cyber defenders
Its hallucination rate on one independent test rose compared with Argon, so verify important outputs

What Carbon can do

Carbon handles about one million tokens of context and accepts text, images, video and speech. Google says its internal teams used it for engineering tasks that ran for several days. In Google’s own cyber tests, it found vulnerabilities in 88.2% of cases on SEC-bench Pro, reached 54.8% on ExploitGym and patched 71.0% on CWE-bench. Google also reports 0% attack success on Gray Swan’s prompt-injection benchmark, and about half as many unsupported claims as Argon.

Who can use it, and what it costs

A motor-show car is a fair comparison. The specs are public, invited drivers test it first, and the showroom opens later. Selected cyber defenders get Carbon this week, followed by partners through Google’s Fairwind Program. Developers, businesses and consumers come after that, with no date announced. The introductory API price is $2 per million input tokens and $10 per million output tokens, with cached input 95% cheaper. The standard price will be $4 and $20.

The caveat most coverage skips

Artificial Analysis found that Carbon answers more questions correctly on its AA-Omniscience test, but its hallucination rate rose from 4% for Argon to 11%. In plain terms, it knows more, but when it’s wrong it’s more likely to make something up. Keep a human review step for anything that affects money, security or customers.

 

What to do while you wait

Take a fintech company in Singapore that wants an agent to review code for security issues. The team can build that workflow on Gemini 4 Argon, which is already generally available. It should also keep a fixed set of 20 or 30 real test cases with known answers. When Carbon opens to developers, the team switches the model, runs the same tests and compares accuracy and cost before moving production traffic. 

 

Frequently asked questions

 

Trending question: When will Gemini 4 Carbon be available to the public?

Google hasn’t announced a date. Access starts with selected cyber defenders and Fairwind partners, and developers, businesses and consumers come later.

 

Trending question: What’s the difference between Gemini 4 Carbon and Gemini 4 Argon?

Carbon scores higher on the Artificial Analysis index (59 vs 50) and focuses on cyber defence and long engineering tasks. Argon is available now, while Carbon is invite-only for the moment.

 

How much does Gemini 4 Carbon cost?

At launch, it costs $2 per million input tokens and $10 per million output tokens. The standard price will be $4 and $20.

 

Is Gemini 4 Carbon more accurate than Argon?

It gets more answers right on Artificial Analysis’s knowledge test, but its hallucination rate there rose from 4% to 11%. Verify important outputs.