Key facts
- Google said Hydrogen scored 54 on the Artificial Analysis Intelligence Index in xhigh mode, against 50 for its Argon model.
- Google said Hydrogen more than tripled Gemini 3.8 Flash's score on Terminal-Bench, a coding benchmark.
- Hydrogen API pricing is $1.50 per million input tokens and $7.50 per million output tokens, unchanged from 3.8 Flash.
- Google said Carbon and Argon API prices rise to $4 per million input and $20 per million output tokens starting next month.
- Hydrogen is live for AI Pro and Ultra subscribers; AI Plus and free users remain on Gemini 3.5 Flash-Lite.
Google released Gemini 4 Hydrogen on November 12, 2026 and replaced Gemini 3.8 Flash with it across the company's products, according to an Ars Technica report by Ryan Whitwam. Access began immediately, a looser rollout than for Google's recent Carbon and Argon models, which started with cybersecurity researchers and were later limited to the most expensive AI subscription tier.
Google said Hydrogen runs in four thinking levels, low, medium, high and a new xhigh, and that even in high mode it is 2.5 times faster than Flash 3.8. The company said its analysis showed the model reduces fabricated claims by more than 5x and more than triples Flash 3.8's score on Terminal-Bench, a coding benchmark. In xhigh mode Hydrogen scored 54 on the Artificial Analysis Intelligence Index against 50 for Argon, per Google.
Google positioned Hydrogen for agentic coding tools, where its speed suits generating simpler code and running tests, while Argon and Carbon remain its picks for long-horizon tasks and security. The model is also integrated with Google Search, which the company called the biggest update to its AI-powered search tools, with better handling of long multipart questions and more visual elements in AI Overviews and AI Mode.
Hydrogen is available to AI Pro and Ultra subscribers in the Gemini app and AI Studio, while AI Plus and free users remain on Gemini 3.5 Flash-Lite. Developers can access it through the API at $1.50 per million input tokens and $7.50 per million output tokens, unchanged from 3.8 Flash. Carbon and Argon cost $2 per million input and $10 per million output tokens, rising to $4 and $20 starting next month, the report said.