Google’s Gemini 4 Carbon is now open to paying developers and Ultra users

Google made Gemini 4 Carbon available to paying developers and businesses and is rolling it out to AI Ultra subscribers, two weeks after a limited release to cyber defenders. It costs the same per token as Argon at launch but uses more tokens per task.

Google has made Gemini 4 Carbon, its most powerful AI model, available to paying developers and businesses, Google said on Tuesday. Two weeks ago, it gave Carbon only to a small group of cybersecurity defenders.

Carbon is also rolling out to Google AI Ultra subscribers, who pay about $100 a month, Engadget reported. They can use it in the Gemini app, AI Mode in Search and Antigravity, Google’s coding tool.

Developers pay $2 per million input tokens and $10 per million output tokens, the same launch price as Gemini 4 Argon. Google says that will rise to $4 and $20 after an introductory period. Carbon also thinks for longer than Argon, so the same task can cost more.

Google says Argon is still the better pick for most coding and office work. Carbon is meant for harder jobs, such as long debugging sessions and scientific research.

The company also previewed /swarm in Antigravity, which turns one prompt into a team of AI agents. Carbon can lead the team, while cheaper models do routine work and others test each change.

Carbon topped the Artificial Analysis Intelligence Index when it first appeared, though its hallucination rate on one knowledge test also rose. Google says Carbon is first on three coding and automation benchmarks run by Cursor, Perplexity and Zapier, at less than half the cost per task of the next best model.

Carbon’s strongest hacking skills stay locked away. A cyber version is still only for vetted defenders through Google’s Fairwind programme. Google says the public version blocked 99% of attack attempts in its own red-team tests.