Google DeepMind introduced Gemini 4 Carbon on October 28, two weeks after Gemini 4 Argon became generally available. Google calls Carbon its strongest model, with particular gains in cybersecurity and long, multi-step tasks. Unlike Argon, it is not open to the public yet.

Who can use it

Now: a subset of cyber defenders, starting this week.
Next: access will widen gradually to more trusted partners through Google's Fairwind Program. Google says it is also taking part in the U.S. government's voluntary pre-release model testing.
Later: developers, businesses and consumers. Google gives no date and says it will open access as soon as possible, after more feedback and work on safeguards.

Carbon is not available in the Gemini app or the public API at launch.

Price

Google has already published API pricing. The introductory price matches Argon: $2 per million input tokens and $10 per million output tokens, with cached input 95% cheaper. After the introductory period it rises to $4 and $20.

Benchmarks, as reported by Google

These are Google's figures:

Overall: first place on the Artificial Analysis Intelligence Index v5.0, with a score of 59.
Security work: 88.2% on SEC-bench Pro (finding vulnerabilities), 54.8% on ExploitGym (exploitation) and 71.0% on CWE-bench (patching). Internally, Google measured more than twice Argon's success rate at writing secure code.
Web development: fourth place on WebDev Arena at 1768 Elo, up 89 points.
Safety: in Google's tests, a 0.0% attack success rate on the Gray Swan indirect prompt injection benchmark, against 0.7% for Argon, and about half as many unsupported claims.

Why access is limited

A model that is good at finding and exploiting vulnerabilities is useful to defenders and attackers alike. Google is giving security teams a head start before wider release, the same pattern it followed with Argon, which first went to vetted cyber defenders for two weeks.

What this means if you use Gemini

If you are not in a security team, nothing changes today: Argon remains the best Gemini model you can actually use, and its $2/$10 price runs until November 30.

If you are planning API budgets, assume Carbon will cost twice Argon's introductory price once the introductory period ends, and check whether Argon is already good enough for your tasks.